Everyone knew it was coming, and I'm going to drop a big spoiler here and tell you that 6th ed is also coming. Businesses are there to make money, and as long as games exist there will be new products. Only a very few games have the luxury of sticking with their base rulesets, Battletech being one of them: it's the advantage to having a sales approach based more on the universe than the rules. If you don't want a new edition, stick with your old one.
Never played 4th, though from reading about the changes I thought Pathfinder seemed like a new coat of paint on the Titanic, and 4th seemed a little bland, though more mechanically sound. I loved watching all the terrible arguments being made about 4th ed, if only because they were the same arguments made about 3rd ed, with the serial numbers filed off. "This new edition is just a crappy Diablo WoW clone for kids with no attention span!"
I played a lot of 2nd ed back in the day, and while it was a terrible system, it was pretty abstract and so tended not to get in your way, which made for a pretty freewheeling fun time if you were willing to overlook the system's flaws (it helped that there were fewer games to compare it to). 3rd ed had some very welcome cleanups, but combat also became more tactical. 3.x ed (and reading on 4th ed) made me realize two things: 1) I like tactical combat, and 2) post-2nd ed systems are just tactical enough to get me to realize that, without being tactical enough to really scratch that itch. I moved to the Hero system.
Also, the idea that 4th ed somehow takes away from the ability to roleplay is weird - there's no story you can tell in Basic or 1st ed you can't tell in 3rd or 4th. Only the numbers change. On the other hand there are systems that add to the ability to roleplay, usually in a certain very specific style or genre by virtue of that system being crafted from the ground up to do so. However, I don't think I'm going to buy any particular effort to tell me that X edition of D&D was such a system, while all the other ones are for babies.