It has been a long time since we played 3.0. One of the changes that I suppose affect the play style strongly where how the "animal buffs" worked.
In 3E, they lasted 1 hour per level and added 1d4+1 to the ability score. In 3.5, they lasted 1 minute per level and added +4 to the ability score.
I think the fixed +4 bonus was "good", since it avoided the Empowering/Maximizing "abuses", while the duration limit enforced a shorter "work day". That might be in a large part because everyone was accustomed to get the animal buffs and not buy the ability score enhancement items, but it might be just that it was still a tactic too good to use.
In fact, this was one of the things we house-ruled, increasing the duration to 10/level. I think that wasn't a real solution, either. At low levels, you had the "short adventuring" day syndrome, higher levels were still as before, except that if you had to travel you waited a little to cast the spells.
Maybe the fix should have been +2 to score, and 1 hour/level duration. But well, that#s house rule territory to counter gameplay changes we haven't even fully discussed yet.
I think some of the spells changed "unfavorobly" for some classes.
Emotion was splitted up in several spells, as was Eyebite. Both were interesting spells for Bards or Sorcerers since they allowed a lot of variety. Nerfing these spells was mostly nerfing Bards and Sorcerers, and I am afraid it let to particular Sorcerers becoming more one-dimensional, and probably typically turning into a evocation specialist (blasting foes into oblivion).
The changes to Flame Arrow (or Fire Arrow?) and the split into Flaming Arrows and Scorching Rays certainly changed the standard low level attack spells around. Melfs Acid Arrow became less interesting, while Magic Missile and Scorching Ray became part the backbone of the spellcaster offensive capabilities. I think this leads to a more "offensive" play style for spellcasters (and also more "burning through spell slots). Though beware: The changes to Haste might compensate this again, since I definitely remember a lot of Haste abuse with spellcasters casting two spells per round.
I think 3.5 was also the time where my group really began seeing the merits of the Wands of Cure Light Wounds - but they were already in 3.0, so this was probably more a "learning" thing and not a revision change.
I am not sure the play style was really changed notably in 3.5. I suppose our group moved definitely stronger towards the "15 minute adventure day", but I don't think that was 3.5 influence, just as "gaming the system".