ExploderWizard
Hero
It wasn't spells that did it, it was move and cast that hurt. Also lack of full attack and movement hurt the fighters. They went from running 30 ft and hitting a guy a few times to moveing 5' and hitting a guy a few times.
Spells did not unbalance, moving while casting did that
Thats a good point. I will add that "turn" based combat combined with not having to declare casting from a pre-initiative standpoint made combat casting much more reliable.
Turn based initiative kind of makes combat feel more like a game and less like a battle. Once you know your place in "the order" you can plan out your moves. As a caster you can cast without much fear of disruption. If someone does want to spoil your spell then they have to wait and do nothing else.
Round by round initiative and spell declaration makes the flow of battle more chaotic and less certain. This gives martial types more power and its been missing since 3E was released.