In my first ever playthrough of BG1 and BG2, I picked a sorcerer and steamrolled over every boss with ease, especially in BG2.
Once I learned Chain Contingency, which can be fired without any delays, I simply loaded 3 skulltrap or 3 sunfire for those with magic resistance and fired it with enemy sighted condition. When 2 CC became available, 6 skulltraps, 3 abidalzim's horrid wiltings + 3 skulltraps, or 3 lower resistance + 3 skulltrap was enough to finish any fights in 3 secs.
It resulted in my sorcerer, who wasn't even soloing, slaying every single dragon and Messisan single-handly in less than 1 second with core difficulty. (the final stage of TOB fight was over in 1 sec, no exaggeration lol) Even before the enemy boss's scripted defense spells were fired, they took 300~400 damages and was out. even if they got their defense up, 3 Pierce Shield immediately followed by attacking spells in 0.1 sec delay put them down.
You can fire 5 CC with 15 spells loaded in 1 sec, no restrictions or whatsoever. And i'm not even done when talking about the OP spell mechanic if you know what i'm saying. Time stop is ridiculous, a set of CCed skulltrap does 20d6 *3 to max of 360 damage, and with improved alacrity and defense spells, your spellcaster, especially a sorc, can beat the entire game without taking 1 hp loss if you are carefull enough.(haven't accomplished it since this was my first run ever, but I think it's totally possible) and there are so many cheese like imrpoved invisibility + spell immunity combo which renders enemy spell casters useless.
I heard BG:EE is not including SCS(which is unfortunate because while they didn't change spells much the improved AI deals with player spell casters rather effectively), if so they should at least do spell overhaul or otherwise this game's battles will be boring as Monday morning for experienced players.