What of the Satyr's Frame?

Right but then you aren't running Wild Hunt. Though I agree with the premise that you are probably better off running Bones or Devourers Host over The Wild Hunt.

I would argue that the theme itself isn't bad, it's the models within it and even then it's not that they are awful, it's simply that it leaves you open to so many poor matchups. I ran it with Tanith for quite a while who does a heck of a lot for it and had a fairly good run. Sic 'em charges off of a Reeve Hunter Weaponmaster charge under Scything Touch and Gang Fighter can get serious work done. The issue is that all the infantry in the list has extremely weak stats. I got to the top table of a local steamroller and ended up facing off against Baldur2. We both knew what would happen but I played it out anyway...Went as expected and lost horribly. The same could be said for any of the armour spam matchups. While there is some game to be had it can simply be done better (and certainly with more survivability) by another theme.

As it stands the Theme is simply a poor man's version of any of our better themes. It doesn't really open up specific matchups that we otherwise struggle with but IMO the main virtue is being able to play lots of single wound infantry. But if you are looking for quantity of attacks why not just take eKrueger or Wurmwood in Bones (AOE's and sprays for days), or Ravagers and Death Wolves in the Devourer's Host (infantry mulching galore).

What was the main topic again???

I have. Its a solid beater. Toss Pathfinder on it, and Im OK with the riphorn. Maybe make it 13pts and its great.

My perspective :

The Shadowhorn is perfect the way it is right now. Don't touch it.

The Riphorn is fine in concept as a cheap beater. Unfortunately it compares unfavorably to the Woldwarden, who costs the same, does about the same damage, and has more utility. Also, the Riphorn's cheaper cost is not significantly different enough from the Feral for the amount of power it loses. Small tweaks are needed if the Riphorn is to see more table time.

The Gnarlhorn is the one that stands out to me as lacking a purpose. Is he supposed to be a cheaper, weaker Riphorn? His weaker stats means he struggles to accomplish anything, even with a buff like Primal. Is he just a slam-bot? Slams are useful but there's no guarantee that you'll need one in any given game, so dedicating a heavy to that task is a bit weird. Fixing the model isn't the problem, its figuring out what the model's supposed to be doing in the first place.

Riphorn is squished between the Woldwarden (tankier, just as fast, hits about as hard, has pathfinder and geomancy) and the feral (hits much harder, more utility, faster, situationally tankier). I think it either needs a new niche in terms of utility, or to become our faction's Skin and Moans equivalent - a beater that does nothing but kill anything you can get it to.

Gnarlhorn is in a weird place. It's output isn't...terrible...for a 12 point beast, but it feels like it's paying for all of the stupid slam tech you'll use in maybe 10% of your games. I feel like it either needs a way to take advantage of slams more easily (boosted slam attacks, +2" threat on slams, etc), or it needs to offer more utility to the list in general - whether that by getting bounding back, picking up something like Rush, or maybe even an animus that hands out counterslam or countercharge (both of which get exponentially better the more models have them.

All of the Satyrs should have pathfinder.

Thing is that a speed buff animus in circle is a very good options inclusion as it conflicts with primal.  As such it offers circle players a choice of, do you want to go further or do you want to hit harder?  Asking 12 points to include that choice in a list is quite reasonable to.

An animus version of Mirage would be super thematic

Didn't wardens recently see a point decrease? Maybe the satyrs will see the same?