Seraph is crap, non-character Nephilim are terrible, how?

Seraph
Slipstream is extremely powerful, it extends threat ranges and allows you to unjam models. Don't forget he just does it too himself as well. Threat range extension is king in Legion (with some list designs).
The gun is for clearing key targets and applying Flare, and a boostable gun with multiple shots is always great.
The Seraph is a support piece. You are not paying 14 points for him, you are paying 14 points because he makes everything else better.

Protector
Niche piece, he lets you play aggressively with your caster. He can turn Rhyas up to 11.

Bloodseer
Another niche piece. He is very powerful when he can use slipstream, and when you are playing magic heavy oracles lists.

Solider
More niche Nephilim. He can scalpel out cortexes, which will protect him against retaliation. He can be worth his points in CotD when he gains unyielding.

Bolt Thrower
You are paying for snipe, he is auto include with the Lylyths and sometimes with eVayl. Again, this is threat range extension. A pow 14 gun is not for taking out Khador jacks, you want to shoot tanky solos, light jacks/beasts. He is also strong in scenario. A base threat of 20 inches is very strong on a boostable pow 14 gun.

All of these models have been used in lists that have won major tournaments, and their relative power is definitely debatable. The Bolt Thrower and Seraph have shown their power over and over again, with the other three haveing more mixed success. If you want specific examples of when you really want something in a list I can provide examples.

Hey, twity

Seraph, even with slipstream, our threat ranges are shorter than other factions. (boundless charge, energizer, 15 other ways to add 2", etc.) If the gun was ROF 2 it'd be much better. When you roll that d3 and it comes up a one, you know you are boosting to hit, probably because you need that -2 defense to stick, everything we have clears chaff/blockers and better too, deathstalker, raptor, for examples.

The protector doesn't even have steady, and he has to be within 3", and he doesn't have counter charge. Knock him over (easy to hit def12) or push him. He kinda does what a 3 point war dog does in Khador when used with Rhyas. (not impressive for 10 points)

Bloodseer, so I have to pay 14+8 points (22 points total) to make 2 models move an extra 2" a turn. That's such a terrible value. I feel like, a simple ice cage can do the same job as Telemetry from further away and it's on models I want use anyway, BFS, Throne, Ice Witches

Soldier, the math doesn't add up though. Who is the target to scalpel a cortex? mat 6, pow 13...assuming you have to burn 1 fury to charge. He can cripple a light jack/beast maybe, something in the 6 point range. Those pieces tend to be too deep to reach with the solider.

Bolt Thrower being auto-include with Lylyth (all) and Vayl has more to do with how weak/fragile those two are. It's an 11 point tax to play 4" further back. (I think he/she/its more realistically 9 points) The animus being range self, and the gun requiring all 3 fury to be useful with rat 5. Very hard to justify 11 points.

I am interested to see the list examples, I am glad you disagree with me on this, because it means I probably overlooked how to use them properly. (I've removed them all from my lists after 8-10 loses late last year)

@ Forever_Blight, lol thanks, that sucks. I took a 3-4 year hiatus from gaming, now that I am back, I'm staring at a half useless collection.

I think niche is okay, the only real problem arises when the niche is there and another choice is preferable. This happens when you have something like the Mk2 shredder. Imagine you are making a list that would really benefit from the Bloodseer, but you would lose tenacity. It becomes a no-brainer, take the shredder.

As far as slipstream goes, you cant compare it to a simple 2 inches of threat. It lets you disengage, move at odd angles, get over the terrain.

Who are you interested in? Of the niche nephelim the only one I don't use is the Protector (who doesn't really fit my playstyle). Still, looking at tournament lists:

Legion Army - 75 / 75 points
(Rhyas 1) Rhyas, Sigil of Everblight [+30]
- Blightbringer [38]
- Nephilim Protector [10]
- Succubus [4]
Blighted Nyss Shepherd [1]
Feralgeist [2]
Grotesque Assassin [4]
Blackfrost Shard [9]
Blighted Nyss Swordsmen (max) [15]
- Blighted Nyss Swordsman Abbot & Champion [6]
Grotesque Banshees (min) [8]
Hellmouth [6]
Swamp Gobbers Bellows Crew [2]

It's pretty easy to see how this could work, with damage amp and defensive tech to allow you to position Rhyas and follow up to extreme effect.

I have a powerful Vayl2 oracles list that uses the bloodseer due to access to slipstream and a high volume of magic attacks making him powerful. My Lylyth3 list uses the bolt thrower for obvious reasons, and my pThags CotD list uses the Solider because he is powerful with FoW and Unyielding.

Blightrain,
im going to have to disgree with you on point cost of the bolt thrower, let's look at trolls real quick.

2 beasts have far strike.
2 casters have versions of it.
Implaer - 11 points
Bomber - 19 points
Gunnbjorn - snipe 2 fury. Yes it affects a unit bit to put it on himself is a wash and at a 6 fury caster that's a strap, Sam can be said for any versions of lylith as well though.

Grim 2 - and it's a feat turn.

It can be argued that the troll beasts are better, but really only because of the crazy buffs that trolls throw around.

Let's look at threat ranges real quick and ignore gunnbjons crazy good gun for a second.

Gunn - speed 6, range 12, farstrike + 4 = 22"
Not bad for 11 points with a crazy good 1 shot gun.

Lyl1 - speed 7, range 12, farstrike + 4, slipstream + 2, apparition + 2 = 27" threat, that's pretty damn awesome for 25 points.

Sure it's only pow 12, but look at buffs and debuff in an ideal situation real quick.

Parasite - -3 arm, and soon we will have a gator attachment that'll cast that for us.

Kiss of lyss - +2 damage

That's a pow 17 at a threat of 27 inches.
Granted that is an Ideal situation. But that is pretty bonkers, no one wants that shooting that their caster.

Twity,
Your statement with sereph and slipstream is 100% on the nose.

I can't count the number of times just that little 2" vector change has put me into a position to go from, "there is no light at the end of this tunnel" , to "yeah sorry you didn't see that man. It really sucks having a ,(insert what ever model you like, my personal fav. Warlord) on your caster.) Lol

Just to day dream for second and a little salt to throw out there, super salty that skarre 3 in getting a version of it, cause yeah cryx needs MORE. And i would like to see slipstream affect enemy models. Cause you know... why not lol.

ok, I'll try and put my pessimism away for now. It's usually not my stance here on the forums. It defeats discussion. Sorry I posted it without adding more.

I have to say that things are not doom and gloom as they seem. On paper we really are lacking. What makes up for it is we still have fantastic strengths. They just don't lie solely in our beasts anymore. If you want to drive the discussion that way I don't mind explaining here or by message.

But for now. Nephilim and you.

Bloodseer - Is not as 1 dimensional as presented. Nothing against your. Ice cage can only hit one target per caster. Ice Cage can miss. Ice cage is a star action. Sacred/Spell ward prevents it's application. Telemetry is a blanket effect that ignores all those penalties. I would take the Bloodseer over the ice witches easily if you're looking for mass spell accuracy. Bloodseer then brings further utility. Crit Knockdown on a boostable attack. 2" reach. Arcane Suppression if you need it. Casting other animi instead. Lastly Arm 18 on an 8pt light is nothing to discount. He seems useless because he doesn't fit the idea of "beasts kill stuff ded". But he brings so much more that's far more valuable. Example of use - He really is the best friend of Hex hunters. Battle Wizard giving a chance at an unboosted attack to kill 2:1 is a great boon of the unit that the 6 to attack with usually undermines. Upping it to 8 makes it far more reliable. Yes you can see that as a "tax" but that argument fails just as much as it does for the "choir tax". Thrones getting to throw up to 4 spells at models outside it's engagement also love that +2 to hit. When you're down to the last BFS member to hit Kiss, again it helps. Magic Sprays from Bayal, Sorc & Helion, Venom on Bethayne, Howling Flame on Kryssa. It always, Always, has something it can do if you want to use it. It's probably the strongest passive we have on any beast.

Bolt thrower - I cannot tell you how much I under estimated this beast. That gun pow is seriously high for a light. The threat range is gigantic. Push on every hit will always ruin those perfectly laid plans on the opponent's part. Knockdown on a crit happens more often than you think, it just might not be at the most crucial moment. Doesn't mean it's bad. Quick work lets it dig so freaking deep into enemy lines. I know it sounds cliche but it is true. But yes he is absolutely a fury hog. Forsaken, shepherds, and gobbers chefs are pretty much necessary anyways.

Soldier - I can't say much good outside of CotD for them. Then need that arm bonus 100% of the time to not be lost to the most average shooting. I use him reliably with Bethayne but not much else. Aby 2 can make him worth his points. But he is in a point bracket where other options do much more.

Protector - The best and only argument is always Rhyas this and that. I used him and a harrier as babysitters for a +3 def swing, parry, and dodge. It never once saved Anything they were meant to protect. He's easily neutered or out right killed. He needs his steady animus back. That alone could change so much for us.

Seraph - Threat range is everything. But good positioning and use of AD/ambush units fix the problem and do far more work in general.

Bah!!! Reading is hard!! Good catch, thanks for the correction.