There are alot of great things about playing BG 1 even after playing BG II. So much is different as far as strategy goes. Charm and summoned creatures are totaly killer. Without killer AC and a bad THAC0 you don't really wanna stand toe to toe with the bad guys for long. Charming an enemy to do it for you or summoning creatures to do it and using missile weapons was alot of fun
Plus I had great fun playing a fighter thief in BG 1. It was soo much easier to stay hidden in shadows before the BG 1 expansion.