Do you think AD&D2e was unbalanced toward non-casters? Do you think in AD&D, fighters were much better than wizards?
Let's see what did 3e mean to fighters:
They lost the unique perc with physical stats: no longer able to have 18/00 str, or being the unique beyond +2 Con bonus to HP.
They lost the unique extra 1/2 attack from weapon specialization. New BAB is somewhat comparable, but it's free for all characters, not something unique to them
They have a harder XP table beyond lvl 9 than before (as the table is standarized now)
Let's see what it did for wizards:
Wizards spells are no longer interrupted if the wizard is damaged in the round before casting it (need to be in the same exact moment, through ready action)
Wizards are no longer fragile: in AD&D2e, wizards had 1d4 hp, +2 max from con. At level 9, that was 9d4+18, for a wizard with starting 16 in con, or 40-41 hp. Now, they can have more than +2 from con, and Con can be boosted with belts/amulets/whatever. So that's 9d4+45, for an average of 60 or so hp at lvl 9 (not including things like toughness)
They get a better XP table beyond lvl 9, as the table is standard.
So, let's see: fighters lost things, and got a worse XP table. Wizards won things, and got a better XP table. In my opinion, either no single edition was balanced between casters and non-casters before the advent of 3e (and thus 3e brought balance to the system), or every other edition was balanced (or closer to balance) and 3e broke that.
They did a lot more to both categories. For Fighter-types, melee damage went up massively. In my 3.5e campaign, the main fighters were competing to do the most damage -- they were doing 200+ per round on "good" rounds. The damage increase was matched by hit point inflation -- especially at levels >9 but even low levels gained a substantial boost.
Everyone got a massive boost to making saving throws at low level -- the bonus erodes at higher levels compared to earlier editions, but the difference at low levels is massive. Wizard spells got capped or reduced damage compared to 1e and had to deal with the same hit point inflation the fighter damage was increased to handle. Further, spells that were restricted by hit point total like Power Word: Kill did not have their thresholds adjusted even though high level opponent hit points trebled or more. Compare ancient red dragon hit point totals and the hit point cap of the power words.