The ability to soulcast is very powerful, but somewhat limited compared to the lore. A skilled enough soulcaster would be able to produce more complicated things, so at ideal 4 i think they should be able to produce smoke and explosions (since smoke and fire are 2 out of the 10 essences), maybe they could be able to get rid of blood loss on a pawn by soulcasting them some blood (another essence). At ideal 5, depending on what you have researched, i think they should gain the ability to soulcast firefoam or tox gas or deadlife dust, these are more complicated than the base essences thus needing both research and a high ideal in an order with soulcasting. These could give soulcasting more utility and combat capabilities than just dissapearing enemies or turrets.

Cosmere 2.0.0-beta.40 | RimWorld 1.6.4871 rev591 | Windows 11 (10.0.26200) 64bit
Cosmere - Core [cosmere.core], Cosmere - Scadrial [cosmere.scadrial], Cosmere - Roshar [cosmere.roshar]