Baldur 2s blood shaman does get to cast roots of the earth, so you can get 4 a turn if you wish. Stalkers, megalith and Loki are all acceptable targets and ghetorix is an incredible one.
Rock wall is also an excellent spell, whenever a caster has rock wall without an exception it's the best spell on their card.
I personally would plan for a list that gets 3 good roots of the earth a turn because baldur will often want to be casting rock wall again to move it up the table.
You do also get the chance to take a blood shaman to increase baldur 2s lists melee damage which Is very useful to have.
I'm not convinced it's competitive, but there are some interesting synergies there.
Some other casters who I think will have a place (possibly not a competitive one, will see) in the post cid world:
1. Baldur 1
Baldur 1 is the caster who (I think alone) runs blood weavers with the UA and gets a lot from the Well. He can make blood weavers into a credible melee threat which is hard to stop due to hit feat and solid ground. Ravagers also like immunity to blast damage and no knockdown and due to blood weavers you can probably get away without taking a shaman for magic weapons.
Baldur 1 is still boring mcboring face, but he has a good list to deliver. I think his (and most DH casters) problem is Wurmwood. Wurmwood does a lot of excellent stuff which also helps deliver and control.
Baldur 1 has a POW 18 lord of the feast with stones kin, which is also really strong.
2. Morvahna 2
Morvhana 2s buffs put her into the excellent category of warcasters. Fog of war is amazing in a list with higher average defence models. Def 15 in one place is merely OK, doing it army wide starts to cause issues.
Morvhana 2 has censure, which is an excellent punishment spell, putting people on edge in a lot of matchups while also having excellent melee prowess herself. Her ability to knockdown, reroll hits and damage rolls and gain additional dice is quite potent. You should see the numbers on her when she has Divine Inspiration, rerolls and also life trader, she *will* remove a lot of heavies in the game pretty casually and repo away.
Her feat allows her to play through hard games where you lose a lot (although it will take a lot of time and effort to work out the best time to feat). Dropping a bunch of ravagers and blood pack on the table will be a backbreaking manoeuvre in a lot of cases.
In all of this, scales of fate allows her army to simply not suffer a huge portion of the bad luck that you could suffer. Rerolls will, in a lot of cases, be functionally equivalent to signs and portents. But mark that she will be spending a lot of her turns healing with fury.
3. Iona
Iona is dull, but she's dull in a strong way. Phantasm and sure foot are excellent spells and her feat is an amazing one because it adds to a lot of your ranged and melee offensive power. She protects your list with 2 good defensive upkeeps, a reasonably powerful defensive aspect to a feat and a elite cadre who can be powerful as long as your opponent isn't careless.
In my opinion Iona is a little lacking in that a lot of her synergies don't work with Death Wolves and LotF, who are outstanding parts of the theme. Her focus on strictly tharn means that she will be running a theme which can try to stat-push your opponents off the table, but lacks the Scalpel and Anvil of those pieces.
She will definitely see play. Big Stats are a fashion that is hard to go out of style.
4. Grayle
Captain "totally a wolf sworn, guys" Himself. Grayle can see some play off the back of him having some pretty good tools like vengeance for bloodtrackers or death wolves, wind blast for close on shooting models like dwarf gun bunnies but honestly the most important thing is that grayle's lord of the feast is actually incredible.
Mat 10 pow 18 with signs and portents at full speed. If you check the maths he destroys a lot of models you wouldn't think he should a not inconsiderable amount of the time.
He destroys a wraith engine 85% of the time if you can thresher another model and kill it (so you can boost the first damage roll and lose nothing).
LotF is probably a little too strong as of the end of cid. If he's anything close to what he is, he will be amazing and grayle makes him best.
5. Wurmwood.
Wurmwood, in my opinion, is the undisputed king of Tharn. His ability to dump himself within 8" of a lot of enemy models on the top of 2 and feat, run his entire army to within charge range and deny enemies the ability to play scenario is exceptional. His ability to threaten and destroy using Hellmouth as well as control huge bases and jacks with stranglehold just allows you to get a nearly insurmountable lead in attrition and scenario in a lot of matchups.
Wurmwood is going to be *huge*.
6. Kromac 2
I am less convinced on call of the wild as a viable theme but kromac 2 already has some rumblings in the meta so he is undoubtedly better than he was.
Pretty much every beast that kromac wants to use is better and so there might be some viable lists.
Pretty much what makes me consider kromacs viability is that the lists that Krueger doesn't want to see are lists with antimagic and large statted models like certain types of colossals and battle engines and kromac likes to see those kinds of lists because he is pretty strong in the stat's on stat's fight. The question is whether kromac in call (or DH) is appreciably better than Iona or Wurmwood or Bradigus at a similar job.