SCS is an increased AI mod that achieves an alternate difficulty setting without cheating on players like by boosting enemy stats and giving them artificial scripts.
In vanilla BG1, it is possible to lure 1 enemy at a time even if enemies are standing right next to each other. BG:EE must do better than this since it uses BG2 engine, but the outdated AI are still exploitable and they behave really, really dumb if you know how to abuse their weaknesses.
a few examples of how SCS makes the game so much more exciting:
In vanilla game, Basilisks/Liches only target the closest enemy to petrify/imprison. You only need 1 immunity protection instead of 6. In SCS they don't *automatically* recognize an unprotected party member. They try attacking the closest first, and then move on to the next target when they realizes your party member is protected from their special attacks.
Immunity:Divination and Improved Invisibility used together was nigh-invincible against any AI. No spell casters without invisibility detection innate ability was ever able to do anything about this, and they just stood there while your character danced, wriggled his hips left and right, song a couple songs, and finally stabbed them in the back.
and there are many more exploits you could abuse with vanilla AI. So far, I haven't found any major exploits possible with SCS mod.
IMHO this is one of those mods that will help the game experience regardless what kind of a player you are, as long as you are familiar with BG battle mechanics. I hoped at least the 'better call for help' component was included in EE, but since it's not been included you might want to check it out when EE compatible version of SCS comes out.
This mod increases difficulty, that's true. But it does it in a way you don't feel cheated. In vanilla BG, your level 3 parties could kill level 16 mage Talantyre with ease - spell interruption. This mod only makes it so that enemies with high levels do have a fair power that they deserve. With a little exaggeration, it almost feels as though AI are being controlled by a human DM.
And if you find this mod difficult, you could always play SCS with normal or easy difficulty. The difficulty will be roughly same as vanilla, only with a smarter, cunning AI that will maintain the same HP, stats and Levels.