[Baalz]

C'tis's major strength is strong mages out of non-capital forts - a rarity in LA. As mentioned, their mages are seem to be custom made for banefire, but even at a much lower research level just skellispam plus fireballs is pretty effective particularly as you mix in a few poison slingers. They've also got some pretty nifty cap only heavy infantry (I prefer the Desert Rangers to the Tomb Guards, much more versatile), and of course the free undead raising though as you mention that tends to be weak sauce as you compare it to LA Ermor.

So, what this says to me (admittedly without extensive C'tis experience) is that what you need is lots of castles. Gold and extra castles are even more important for C'tis than most nations because what you need to do is make lots of mage factories. Your research isn't subpar from that point of view, compare the sauromancers to other non-cap mages. Your (relatively) free undead are not the centerpiece of your strategy as they are with Ermor, they're just some disposable free chaff that is there to tie up the enemy while your superior artillery rains down on them. Ideally you want to minimize the amount of infantry you recruit so you can focus on maximum mage output, that's where the free undead come in. You don't need overwhelming undead numbers like Ermor does, you just need enough to keep the enemy archers busy while your skellispam shuffles up so your mages don't get hit.

Because of the AOE of the slingers and lack of stacking you just want a handful. Likewise you just want a handful of heavy infantry guarding your mages from flyer/flankers. Next, you've got to realize that a mage-centered army is just that, and you need critical mass of mages because you sure can't count on the longdead to carry much. If you focus tightly on getting mages you should have a lot more than your typical opponent, so don't feel bad about pulling some of them off of research much earlier than you usually would to rain down the pain.