I loved 3rd edition for years, but was fairly exhausted by a few key aspects of 3rd edition by the time 4th came around. Basically, it became less about playing the game at the table and more about playing the game - like a mix of wargaming and accounting - off the table. Character and monster building, planning 17 levels out so you made sure to take the feats in the right order to get the levels of your 4 classes to do the... spell synergy this, special item that, etc. I'd already been trying out all kinds of variants to see what worked: Mutants and Masterminds, True20, and other systems, while thinking fondly back at my D&D Cyclopedia, pondering E6, and eventually running custom versions of 3e that simplified things down a lot, especially on the DM side of things.
Then 4E showed up, and it had its rough edges, but it was a lot of fun for a while as well. The biggest shame was on the marketing and legal side. How the heck you screw the pooch so badly with Paizo, Necromancer, various old hands. Though I'll grant that they also tried to shoehorn the PHB far too much. They needed a mix of options, not _just_ the same layout. Not courageous enough. 4e's still got its problems, which clearly aren't going to get attention now, at least not from WotC.
I'm not really seeing that D&D Next is going to answer everything I'm looking for, but I'll play it a bit. 13th Age OTOH has been a blast so far. A couple proud nails, I'll admit, but it's a _lot_ closer to the "somewhere between BECMI and 4th" that I'd been pondering. I'm a bit more reluctant to dive wholehog in like I was on 3rd and 4th. So maybe I'll just play a variety of systems again, like I used to back in the 2E days where we started up a new campaign with a new ruleset every 3 months.