My approach and hope for 5E is quite different. I don't want an incrementally improved version of a specific edition. What I want is a new edition, one that hopefully takes the best elements of other editions and re-works them into a new whole.
I think the issue is one of degree.
4E was drastically different than earlier editions. 3E was also drastically different.
So, let's take something like feats. There were effectively 7 versions / subversions that did not have feats and 4 versions / subversions that did. I think one can pretty much assume that feats are not going to be dropped out of 5E. They are too integral to the last 11+ years of D&D, even though there were not in the first 26 years. It's unlikely that the 5E game designers are going to make feats an add on module. If someone doesn't like feats (and there are some things to not like about that particular game mechanic), they will pretty much be in the same boat with 5E.
You might think that feats are one of the best elements of various versions and another player might think that they are a hack.
So, this is just one example of where one person's best elements does not agree with another person's.
Because of this, I think that 5E will not even attempt to be the best mechanical elements of earlier versions, but more the best feel elements of earlier versions. Vancian magic will be back. Ability score checks will be back stronger than in recent versions. But, the mechanics of these earlier edition elements will probably not be the same as earlier.
The idea is not merely a new edition of D&D (although that will happen), but rather a stronger D&D flavor edition of D&D. For people that loved and still prefer 1E, 2E was a slightly different flavored D&D, 3E was heavily different flavored, and 4E was really different flavored. The game morphed a lot.
As an example, the utility of the Invisibility spell went from extremely useful to nearly useless over the various editions. Wizards used to take it all of the time, even up into the 3.5 days (although it was a lot less useful even then). In 4E, Wizards almost never take it. That drastically changes the feel of the game for some players.
4E introduced powers. That drastically changes the flavor of the game for some players. Elements like a lot of first level and racial teleportation changes the feel for some players. 3E not only introduced feats and prestige classes, but it also introduced the Christmas tree of magic items.
In order to gain back a lot of gamers from a lot of different editions, I think the designers are going to go with a more middle of the road, quasi-2E type feel (not necessarily mechanics, but feel), and then having classes and modules to add back in some of the more recent non-earlier flavor type feel elements from the last decade plus. Not so much the best elements of earlier editions as you indicated, rather, the best feel of earlier editions with add ons to hand back some of the feel/mechanics of various editions.