Those on this sight who are heavily entrenched in 3.5 have found insult in their enthusiasm and have taken it as an insult to the game they love. My advice: lighten up and let's wait for the game to be released so that we may fully evaluate it before we write it off.
For me, personally, I don't have much invested in 3.5. I'm a slut for new games and new systems, and I'll play and kit-bash anything I can get my grubby little paws on.
But a lot of the reasons they've been giving for the switch seem to lay definately in a more subjective realm.
I mean, take the halfling issue just as an example. In the same game where they're espousing the idea that D&D is about playing a game, not simulating a consistent world, they're sprouting the lil' guys up in height and weight but leaving them Small-sized. The reason? Not playability, not speed, not elegance, but "believability." Because apparently it's unbelievable for child-sized people to have slightly less strength than an average Human.
That's the kind of thinking that leads to people seeing 'change for the sake of change' and 'a few designers' house rules' and 'implying that the other way sucked.'
Smaller halflings weren't inherently unbelievable, but a few designers (and possibly some vocal critics) thought it was, so they changed it despite the objections of those who were okay with it, and then said that it was so much better that way, despite not really adding much, if anything, to the game.
I, personally, don't have much invested in what size and weight halflings are. But their motive for the change is goofy enough that I don't believe it's justified. And once you've seen one or two things like that, it's much easier to see that in future installments, and when they start talking about how obviously superior the game is, it brings up an instant reaction of "Okay, you think so, but you're obviously not playing the game the same way I am, let ME judge it."
Wereas with 3e, most of the changes really sounded like the designers were playing the way most people played. 3e has some endemic problems, but pointing out those specific qualities that are being designed away from is much more constructive than just spouting superlatives.
In short:
"We're making Grapple rules simpler. It will now involve less d20 rolls because it will be more abstract." rather than "We're making grapple rules better."
"We're making touch AC more elegant. It's being rolled into Reflex saves." rather than "Touch AC was a horrible mess!"
"We're giving you a core setting to help newbie DM's. It's basically going to be an assemblage of random proper nouns and examples of how to design things." rather than "Greyhawk was legacy crap."
"We want making monsters to be easier, so we're going to call out exactly what characters are capable of taking on." rather than "Monsters following the same rules as PC's lead to a bloated, horrible, boring process when making new monsters."
It's totally possible to be positive and energetic about the new edition without complaining about how it sucked under 3e. If people agree with you, they already do, and if they don't, then telling them how much it sucked isn't going to win them over, but showing them exactly what you plan to do might.
