Willie the Duck
Hero
There were some other systemic or conceptual changes as well. One I remember is: in 3.0, getting a special ability on a magic weapon would cost pluses, so a +1 flaming sword would effectively count as +2, for instance (in gp cost, level needed to make, whether it counted as epic, etc.). However, enemies might have Damage Reduction of '30/+2', against which the +1 flaming sword would not penetrate. Thus there was a strong incentive to always just take the pluses. With 3.5, they (presumably thinking games with energy weapons were more fun than everyone just chasing pluses) changed it so that Damage Reduction was more like '15/magic' and thus any magic weapon would work, (and the flaming would just be a overall plus to the gp cost, kinda solving the problem twice). There were subtle little quality of life changes like that. They just usually get dwarfed in the discussion by the larger concerns like the devs bizarrely picking on small races or them not fixing spellcaster vs. fighter/monk/everyone else, etc.It has been a long time but my impression was the change was mainly about fine tuning numbers, making miniatures more essential to the game, and nerfing some of the abilities (this last point may be debatable).
There certainly is an aspect of that. Just how much (and how many ways) they tried to make sure extra attacks didn't run away with the game -- no more than 5' step to get multiple attacks, massive feat trees for two-weapon fighting, amulet of mighty fists* costing 3x what an equivalent magic weapon would cost, etc. -- suggest that they really thought that whatever was a problem in 2e would be the problem in 3e. They also just did some things like realizing that X in 2e was widely considered unfun, so changed it to something else without reassessing whether the new version would then be unbalancing . Such as - no one liking being a caster whose spells are constantly disrupted, and when they do get to cast them they end up facing fixed percentage** Magic Resistance and enemies that saved X% of the time, regardless. So they changed it, making magic more reliable, easily cast in-combat (even without a special feat, just a skill check), and significantly more likely to land on the opponent -- without thinking about what that did for caster-noncaster balance.3e was made on the idea that it would run like 2e. The problem, they changed so many rules that it was nothing LIKE 2e in how it could be used and abused. They closed several loopholes for power gamers and munchkins that were in 2e, only to open a HORDE of loopholes for them in 3e.
They didn't expect people to analyze the rules and then change the way they played accordingly. They didn't expect that it would be the RULES changing to feel of the game and the way people saw how it could be played. This unexpectedly meant that there were players out there that found these new loopholes to create crazy chaotic unbalanced insanity in the game.
*which would apply to offhand and flurry attacks as well as your regular allotment.
**changed from 1E, where MR went down 5% per level over 12 the caster was, IIRC.
I don't know that 3.5 really did anything to fix balance. I remember Natural Spell becoming core in 3.5, and many of the persistent balance issues (other than haste) not really being addressed.3.5 was their attempt to bring balance back to the game. It probably worked for around 3-6 months. Then it became crazy again.