I agree that 5e is a pretty good mix of old school (I.e. pre-3e), 3.x, and 4e.
What do you mean by "Gridded combat"? Just to explain where my confusion springs from: . . .
The thing I like the most about 4e combat is the importance of positioning & then also forced movement effects & the control they can give. I very much doubt this will ever really be a feature of 5e as it would be tacked on rather than baked in.
I mean specifying exact squares. For example, if you're playing a wizard and you use Thunderwave to push a pair of goblins, do you push one of them to a square adjacent to an ally? Do you push one onto a square that you know is trapped? Is your front rank spread so evenly across the whole room that not a single goblin can charge through the front rank toward the wizard in the back without provoking one (and possibly two) Opportunity Attacks? Having exact squares makes those things unequivocal, whereas without them, the DM has to make a judgement call.
Of course, that (judgements by DM) is the original style of D&D; but 4E got fairly far away from that in terms of positioning. Perhaps the 5E DMG will bring that back as an option. If that doesn't make my meaning clear, then I don't know what else to say.
I mean specifying exact squares. For example, if you're playing a wizard and you use Thunderwave to push a pair of goblins, do you push one of them to a square adjacent to an ally? Do you push one onto a square that you know is trapped? Is your front rank spread so evenly across the whole room that not a single goblin can charge through the front rank toward the wizard in the back without provoking one (and possibly two) Opportunity Attacks? Having exact squares makes those things unequivocal, whereas without them, the DM has to make a judgement call.
Of course, that (judgements by DM) is the original style of D&D; but 4E got fairly far away from that in terms of positioning. Perhaps the 5E DMG will bring that back as an option. If that doesn't make my meaning clear, then I don't know what else to say.
I think more tactical play like 3rd and 4th presented: 1-2-1 diagonal movement, more causes of opportunity attacks, maybe more frequent opportunity attacks, and other things that rachet up the tactical/mini-based nature of combat.
Best from 4E - This is where I most question the statement. There are a couple elements that seem taken from 4E, such as surge-like healing, but it seems that the aspects of 4E that really stand out as unique - namely the AEDU paradigm, power sources, and tactical combat - isn't there. Yet. So while it is easy for me to imagine 3E-like customizations, I'm not sure yet how 5E wil provide modules to simulate a 4E feel.
So far it seems that fans of 4E are most displeased with 5E, and it is hard for to imagine how this will change - although it is possible with the right module in the DMG. But that would have to be a helluva module!
What do you think? Does 5E seem to capture the best from the last three editions? If not yet, do you think it can?
Innovations from 4E that are still missing:
(1) "Page 42" -- the default list of DCs and monster strength for actions the rules don't (explicitly) cover. That would be coming in the 5E DMG, I guess, but we haven't seen it yet, so it's too early to say it didn't carry over.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.