I'd like to tease out and clarify one of my points, which is that the "4E crowd" doesn't have as distinct or faithful or, probably, lasting an identity as the "3.x crowd" (which has largely morphed into the "[notranslate]Pathfinder[/notranslate] crowd"). I've said this before, but it is my sense that 4E will be similar to 2E - sort of lost in the mix, with some continued players but less than the editions before and after it. I imagine that there are less people playing 2E than there are 1E (or a modified 1E, or OSRIC).
I'm sure someone has said it, but it might be that D&D editions are like Star Trek movies - it is the even numbered ones that get re-watched ad remembered (although 1 is under-rated, imo, and 3 was decent, if only as a bridge between 2 and 4, the two best ST movies imo; and of course after 8 it all went into the crapper...but I digress).
I guess I am a hardcore gamer of wargames, RPGs, and many non-wargame board games (even a handful of non-collectible card games). I've been gaming for roughly 40 years and RPGs since 1974. I go to at least a half dozen gamedays and conventions every year and play in a somewhere around a dozen RPG systems each year as well. I've known relatively few single-system RPGers in my gaming life, that is those who play only a single RPG system year after year for a few years or more. Multi-system gamers (that is, those who play a number of RPG systems during the year, most year of their gaming life) have systems they really love, some they will play if invited whether they love them or just like them, some they have tried and don't like/play, and some few systems they simply don't care to to even try because of what they have discovered about them. They can generally glance through a book or check out a demo of a system, new or old, and decide if it is something about which they wish to spend any time discovering more.
I've largely been a "single-system gamer" although not by choice. I've played games other than D&D throughout the years, but rarely more than for a few sessions and not as frequently as I would have liked. A large part of this just comes down to availability and convenience. Right now I'm the only "serious" gamer in my group, so I'm the only one who has a sense of the breadth and depth of the RPG world or who owns multiple game systems. But I think that's just it: groups comprised of hardcore and serious gamers are more likely to play multiple RPGs, whereas your typical D&D group - which is usually comprised of one or two serious gamers and a bunch of casual gamers - just plays D&D and never really veers from it.
I've been running 4e since slightly before release. During that time, 4e's warts have become increasingly apparent to me. However, the same thing happened with every other edition before hand, so you know. I suppose I'm most in love with 1e, but it lacks key elements for me... likewise every other edition so far. So I'd say I'm a casual 4e player. (Well, dm.) Regardless, I'm part of the "4e crowd", I suppose, since I've been running it for years and have no intention of moving back to a previous edition.
5e is looking promising to me: enough customization, enough simplicity, fast enough play, enables mixed level parties (so every pc starts at 1st level is a viable playstyle), etc. It enables the type of game I want to run. It ties things to the campaign world (the traits you get from backgrounds are great) and encourages the pcs to make use of those character backgrounds. So far it looks awesome to me. So when it actually releases, I'm very likely to be a first-day adopter. We'll see. If the game looks to suck, I won't buy it- but so far, I'm thinking it's going to be my new best edition ever.
This all sounds very similar to me. For awhile I was thinking of changing it up and converting our group to [notranslate]Pathfinder[/notranslate] - I even bought all three bestiaries and the intro box (I already had core an the GM's book) with that in mind - but when it came down to it, when I scoured over the rules, I remembered some of the things I didn't like about 3.5 and it also brought to light some of the things I really liked about 4E.
Part of the problem for me with 4E is that it seems like it took a half step forward but also a half step to the side, rather than simply a whole step forward. To put it another way, it moved beyond 3.5, but didn't either adequately include its best qualities (classic D&D feel, customization, flexibility) or fully transcend its worst qualities (unwieldiness and over-complexity). What I've seen so far about Next is promising in this regard and I'll be glad to adopt it if it comes close to fulfilling that promise.
5E doesn't have to be a perfect game - it won't, cannot be - but it must address the biggest problems of 4E, include the best qualities, and re-incorporate the best qualities of prior editions that were lost -- at least to some extent.
