Part of the question is - who is the player base? I switched my GMing from Rolemaster to D&D precisely because 4e was a radical break from earlier editions, which I had no interest in GMing.
The problem for WotC with a strategy of releasing a 5E that drops "narrative-driven metagame mechanics" and heads back into the direction of 3E/PF is that it will cost them GMs like me. How representative am I - I have no idea, but I don't feel that unique!
As regards narrative-driven metagame mechanics, I don't think it needs to be a big deal. A few powers like "Come and Get It" would need to be rewritten or deleted. We'd see more Essentials-style classes and fewer Vancian casters in drag. Healing surges and full daily healing might be replaced with something else, or they might just get a facelift to make them more palatable to the simulationist.
And I'm certainly not proposing taking 4E back to 3E/PF! That's the last thing I'd want to see. I myself am a 4E DM, and 3E is the single edition I never want to run again. I could be talked into running either edition of AD&D, I rather like the idea of giving BECMI another go sometime, I might even be willing to take a stab at OD&D, and I wouldn't mind
playing 3E, but DMing a 3E game... hell no.
However, I think there are a lot fewer irreconcilable differences between the 4E and 3E/PF fanbases than people think. Probably the biggest complaint I've heard about 4E
as a system* is that it's "video-gamey," by which the complainers seem to mean that it doesn't pay enough attention to crafting a believable and coherent world. I don't think many 4E fans would object to the system doing a better job crafting a believable world, so long as it didn't undermine 4E's strengths of clear rules and ease of play.
[size=-2]*The other complaint I hear a lot about 4E is, "I've already got hundreds of dollars' worth of 3E books." There's not a lot WotC can do about that one; they really
would have to go back to 3E to tackle that concern, and then you'd hear the exact same complaint from 4E gamers. This is why I suggest waiting until boredom starts driving people away from 3E, Pathfinder, and 4E alike.[/size]
Isn't this an upshot of the OGL in combination with the SRD - if not forseeable at the time (presumably Ryan Dancey didn't foresee it) then not so surprising in retrospect.
I've been thinking this very thought. It's ironic; the OGL/SRD was created as "one system to rule them all," with the explicit intent of killing off competing rules systems. WotC wrought too well.