I don't recall there being this level of dissent (but I could be remembering wrong). It was the exact same sort of stuff, but it seemed much more 80/20 or even 90/10 pro-against. This time, it's much closer (50/50, 60/40, 40/60 - depends on which messageboard and which forum within a messageboard you go to).
I'm certainly not anti-4e. There's some stuff I like about it. But there's enough that I don't like that - for me personally - I'll probably be sticking with 3.5 (or 3P - Pathfinder RPG). I was excited for 3e when it first came along because it seemed to largely keep what I liked and fixed much of what I didn't. With 4e, it's changing not just what I didn't like, but also a lot of what I *do* like. For me personally, the fixes have crossed the threshold of what I was comfortable with changing. To jump entirely to 4e, I would lose almost as much that I enjoy as I would gain. Tweaking 3.5 (with Pathfinder RPG or heavy house rules or whatever), I can have most of the fixes without losing what I still enjoy.
Besides, I play fast and loose enough with the rules when I DM, that I'd rather fudge numbers through a complicated high level combat than have a system with perfect math but fireballs aren't a handful of d6's, wizards don't have hundreds of spells each level to choose from (and each a couple paragraphs of some weird effect), the Great Wheel with the Blood War, having to wait a year (or more) for the content that I have already, and so on.
For some, what I have loved about the game since I was a kid are areas that they feel need fixing, and they probably love 4e. That's cool with me, I can understand that. But for me, from what I've seen so far, what I dislike about 4e far outweighs what I dislike about 3.5. So it'd be easier to hammer 3.5 into my perfect game than 4e. (And, for the record, I've been playing since red box days.)
Of course, once I try out 4e, I may be entirely wrong, but after the previews at D&DXP, I'm much less excited about 4e than I was beforehand.