I am thankful for 3E for giving me the games that I wanted.
2E made things very difficult. It was dry, flat, and every fighter was no different than any other fighter other than their choice of weapon specialization. Meanwhile, me and my friends were young, in junior high then heading into high school, and we were completely HIGH on DBZ, Street Fighter, and other visually-satisfying, massive variety, awesome power entertainment seen in japanese-anime and video games.
Always there was "I want to be this, but be able to do that, but do this also, and I can deal with not doing this or being so so at it" but 2E didn't give the options and structure to do so. And it felt like D&D Twilight Zone whenever we began house ruling our own stuff into the game. But we dealt with it.
Soon, EVERY character multiclassed in our sessions. It wasn't a matter of power-gaming, no. It was a matter of developing a character and keeping to the rules and game mechanics at the same time. We've had Fighter/Song Mages, Psion/Fighters, Fighter/Mages, Ninja/Mages, etc. Thankfully, 2E had come out with Class Kits, Player's Option books, and the DM's Option: High-Level Campaign book. Also by then we did away with racial restrictions to both levels and class. In a sense, we were slowly transforming our games into a 2.5E without realizing it.
Someone mention in this thread that he remembers when he had an elven Fighter in 2E but played him like a knight. He didn't need PrC, feats, or whatever to tell him so. But it's not just how you play a character that separates you from the rest, it's also what your character can do and the abilities he or she possesses. Sure, play your Fighter as a knight, but without the Knight class they have in 3E, can your fighter call out his foe, continue fighting in the negative hit points, automatically receive a benefit to ride better than a Fighter (their free Mounted Combat feat), have more willpower than the other guy, etc., etc.?
No.
He was no different than the other warrior except by title. Nowadays, you can always have the unique character you want. Did you know that we even role-play in story arcs how the characters receive their feats, skill ranks, and class abilities? I remember when my friend's ranger acquired 4th-level, he was with his character's uncle, a 7th-level Ranger of Mielikki, and together they went to a religious holiday of their religion set on the autumn equinox. It also happened to be the character's birthday, as well. After celebrating and performing sacred rituals, the character went off alone to receive his deity's blessing. After some prayer in a secluded grove with a sparkling pool of water, his first animal companion arrived as both a gift and a blessing that Mielikki was proud of him and his deeds. He also intuitively received a connection to the Weave and then through his goddess so he can acquire the divine spells she will be granting him when he asks each morning.
But, my point is this. 3E offers what D&D has never offered before. More and more options to keep the player satisfied. As opposed to "Sorry, you can NEVER be a dwarven wizard. 2E rules say you can't" or "Sorry, you can never rise equally as both a decent warrior and an arcane spellcaster without falling behind from your allies" (thanks to Eldritch Knight, yeah you can)