So, out of curiosity who do you like caster wise, what do you like in the list and why? On paper I think I like grim a lot, his feat helps counter some of the saeryn shenanigans and his debuffs (assuming he can hit) help deal with their high def. Calandra might be good, but I am worried that their awesome assassination game puts her in the dirt.
As for beasts/units/solos my thinking is:
bomber - is always good and the typical high def / low armor of their troops is somewhat mitigated
ebdt - fairly high pow on weapons that I can steal. plus pathfinder is a decent counter for pathfinder
fell caller - mat bonus and stand up are never bad
janissa - walls are great especially with their average to low mat/rat
runeshapers - (with janissa especially) because they can't count on high def/armor to protect them as they walk out of combat and aoes are good vs high def
kriel warriors - cheap and with medium base size can really take up a lot of table space and mitigate flyover shenanigans and cma and prayer can help hit high def reliably
pyre troll - damage buff and elylyth immunity
mulg for being mulg - although his animus is great at removing tenacity and spiny growth
fenn blades - speed and vengeance can help with their speed above average mat helps
and not so good:
burrowers - so many serpentine models can't be knocked down so their low mat really hurts them
scattergunners - high def again points out their low rat
Anyway, just some of my thoughts while on a lunch break. I'd love to hear your thoughts.