The big news in the tabletop roleplaying world lately has been the announcement and open beta of D&D Next, the "next version" or "next iteration" of D&D. Deliberately not called "5th Edition," D&D Next is supposed to be the "edition-less edition" or the "edition that unites the editions". One of the big themes in its development is trying to make fans of all versions of the game feel comfortable with and excited about it. To accomplish that goal, Wizards unleashed a massive open playtest. It's an especially savvy move on their part: it does give the fans some say in how the next version of their game develops, and it gives Wizards a boatload of free market research data.
Of course, it's completely transparent that Wizards really wants "unite the editions" to mean "get players who used to play older editions back playing our game". Figuring out exactly which players they're targeting provides a fascinating lens to view the development of D&D Next through.
Surely, there are groups of players who are stuck somewhere in the 20th century, who still play various expressions of 1st and 2nd Edition. It's safe to say that these aren't the gamers Wizards is looking for. It's nearly impossible to say how many of these gamers exist, but it's conventional wisdom that there aren't many of them--and from personal experience, you need to hang around a local gaming scene for an especially long time before anyone seriously brings up playing 1st or 2nd Edition. And even more to the point, if they haven't taken the plunge and switched to either 3rd or 4th Edition by this point, it's unlikely they'll be lining up to switch to a new game.
At the opposite end of the spectrum are the 4th Edition players, who it's probably assumed will naturally switch over to Next without much hesitation. It's a good assumption for a couple of reasons. First, 4th Edition players already play the version of D&D that's arguably the most different of any of the versions out there, so they're relatively likely to accept changes to their game in the interest of a more fun, consistent gaming experience. Second, while 4th Edition is played and enjoyed by many thousands of people, its fans have never been the sort of fervently defend it and therefore seem like they'd be more accepting of switching to a new system.
That leaves one category of players, ones who do fervently defend their system and have proven to be less accepting of switching to a new one: 3rd-Edition people. Some are still playing "vanilla" 3E; probably more are playing Pathfinder, a licensed derivative. Pathfinder fans are disproportionately likely to be apologists, readily reminding you that Pathfinder has now surpassed 4E in terms of sales and has a more vibrant organized play scene. It's a big group of gamers, one that until three or four years ago played on the cutting edge of D&D but were turned off by some of 4th Edition's bigger revisions.
I won't go as far as saying that D&D Next is a ploy to get Pathfinder advocates and 3E adherents back into the fold. But those are the most natural segments of gamers for Wizards to try to appeal to with the new set of rules. And it explains why a lot of the mechanics in D&D Next might have a very 3rd-Edition feel. Some of that distinctly 3E feel is already present in the playtest rules; check back for a first-glance reaction to the first beta.