It want BG. A FF Tactics like 4e wont even touch the effect BG had to the broad market regarding D&D.
You appear to have snipped the substantive part of that paragraph:
Thankfully, exploration is not something that is limited to 2E, and so a 4E BG-ish game could similarly feature big expanses of darkness to uncover. You seem to be under the impression that a 4E game must be in the mould of an X Tactics
Yeah, that phrase of yours does not make the contest clear enough. You do not seem to understand the why, I wont bother saying again the same things.
I do understand the why. It would appear that you have not properly thought through your objections to a 4E-ish BG, and that is why I was able to refute them. (And the biggest design problem -- how to handle immediate actions -- you even solved by yourself!)
So what about combat? Would it be like jagged alliance? Would you build the game on more big grid maps?
Well, what I would LIKE is a game that is turn-based using squares, but with the ability to use real-time for the less challenging encounters (much as you would have in a BG-ish game featuring random monsters). You would also have maps to explore and plenty of space in the middle to go exploring -- but not too much, because wandering around for too long results in loss of focus. You would have things tighten up again close to the end, and the pace of the game would accelerate as you neared the final fight.
You would have plenty of gorgeous cinematics, ideally of the same quality as Mass Effect. You would also have plenty of dialogue that allowed you numerous options that really let you find a good fit to your character's personality. Some of these dialogues might even have repercussions further down the track; none of them, however, would deprotagonise you in the sense of leaving you thinking you'd been conned or left in a lose-lose situation. Oh yeah, and it would have Jennifer Hale voicing the protagonist.
Because in the end, it's all about Jennifer Hale.