Technically, as a system, sure 4e was superior to 3.5 - it was just a better-balanced, more consistent, more playable system. That doesn't make it fun, just technically well-executed. Lots of other things besides nostalgia come into whether you like a game or not. A technically well-done game can be extremely dry and boring in delivery, for instance, and that can put you off whether you've ever played any game before or not. A good system can be married to a bad setting, or vice-versa. 4e had virtually no setting at all linked to it. Right there, if you like a wealth of evocative setting information, 4e failed to deliver much of anything.
Well part of this is opinion based. I find that with some people they find that Pathfinder is the better, consistent and playable system.
Then, there are things that are technically 'good' or, say, more sophisticated, that people just don't like. There are people who prefer ordinary breaks and manual transmision. Modern anti-lock breaks and automatics actually perform /really/ well now, but some folks prefer the sense of control they get doing it themselves. 4e makes the DMs job a lot easier - that makes it a better system, but, it also gives the DM the sense that what he's doing is less important or more constrained (it's not, he can ignore any rule or guideline he likes), but the sense of it can be quite real.
Also a matter of opinion. Some people find that Pathfinder is a lot easier to DM than 4th edition. It's better for some but not everyone.
There's also play styles. Certain aproaches to game design yield games that favor one style or another. 4e was a good game that works well with an abstract or narrativist or gamist style, while 3e was a pretty good game that really catered to a simulationist style, and AD&D 2e was a pretty poor game that tried to apeal to setting-oriented a 'storytelling' style that was in vogue in the 90s, and it's predecessors were positively primitive games that apealed to (or encouraged?) an explorative - I'd even say 'paranoid' sort of style.
And, finally, there are those who don't like what a good system accomplishes. Balance, I think is the most obvious culprit. A balanced game is great because it provides a lot of viable, meaningful choices, and a relatively new or casual player can build a straightforward character that's viable alongside a more experienced or determined player's carefully-optimized character. That is, it's great if you think 1000s of hours of RPG experience, and meticulously masterful character building shoudn't be rewarded in play. 3e - according to one developer who worked on it, anyway - intentionally includes overpowered and 'trap' options and power combos to 'reward system mastery.' 3e was not exactly a dismal failure, in spite of all the complaints aired about how 'imbalanced' it could be.
I will say that 3rd edition was made easier with system mastery but that is actually more of a play style. Being a system geared more towards intermediate to expert DM's doesn't make the system less or inferior.