Yes, It can really make things tough in the beginning. As stated, it REALLY improves the tactics of enemy spellcasters, they become ferocious. I had to un-install a few of the options until my party is a little tougher. It was throwing Liches around as random dungeon encounters! I was doubly screwed because their spellcasting was vicious!
On a side note, if you have The Darkest Day installed, make sure that you only install the TDD-compatible elements of the mod. In case you do, you can find a nice list in this forum:
http://www.teambg.net/forum/?board=1...;threadid=7815