It seems to combine a lot of the things I like from BECMI, 2e, 3.x, and my own homebrew add-ons that I really liked, and makes the things about 4e that I didn't like, like skill challenges "die in a fire".
So from BECMI, it is going back to a more basic style of game. I like that. Also weapon types getting special abilities as you improve, that seems to be a bit of a throwback to BECMI Weapons Mastery (which as I've said before, was the best thing any edition of D&D ever did at any time in the history of all roleplaying games). Also we go back to the "jolly hobbit" halflings and not the tiny lithe cone-heads of 3.x or the boot-wearing river nomads of 4e.
I like that (at least from what I can tell so far) they are going with "what makes sense" and "what sounds cool" than by "what's balanced?" and "what's the math formula again for figuring out saves/to hit/etc per level." That's old school, in a good way.
From 2e, we have "Themes" which seem to be akin to "Kits" which I envision as a very good way to make subclasses, etc, without having to make entirely new classes.
From 3.x we have true multi-classing, but hopefully without the "saving throw suicide by design" wonkiness that happened in 3e with some multi-class combos.
From my own homebrew, we have ALL THE STATS mattering for saves. In BECMI my house rules were STR bonus adds to save vs. Paralysis, Con adds to poison/death, Dex to Breath/Traps, Int to Spells, Wis to wands & other magic items and Fear, and Cha affected to all saves (so don't use it as your dump stat). What they seem to be saying is very similar; that you may need to make a STR save vs. Paralysis, or being grappled, or to burst free of some ropes; but you may also be able to argue with the GM that you could slip free of the ropes using Dex. I like that.
I also have to say I like the descriptive skill system. Get +X to whatever I make up that I do with STR. Cool. So I could get +3 to STR checks to bend bars/lift gates, or +3 to STR checks vs. poison, or +3 to Str Checks for doing athletics, or wrestling, or whatever else I want to describe. That's nice because it doesn't confine me to a finite list of "what you can do (and the unsaid "and what you can't do" part that I hate about such lists). It really allows me to do anything. If I realize at the end of a session that I wish I were better at escapology, maybe later on when I have some points, I'll put some towards that.
On top of all this, it seems like "we may be getting the band back together". As in the adventuring band... my group that FRACTURED over 4e (the GM and 1/3 of the group really liked 4e; the remaining 2/3s (among whom was the homeowners where the weekly game was held) hated it with unabashed fury. I was ambivalent to it. Since I drove over an hour to get to game sessions and my wife limited me to 1 game a week, this meant throwing my lot in with the players who didn't like it. I just wasn't going to drive an hour to play 4e D&D, but I'd drive an hour to GM BASH! for the group.*
*
The one major upside regarding 4e for me is I (who normally never got to GM this group) got to run a couple really long BASH! and Honor + Intrigue campaigns because the regular DM was no longer DMing the group due to the 4e Schism.