not to mention WoC has had the trend of changing adnd rules versions more often then microsoft puts out new windows, makes it unlikely we will see any comeback. Thank god for the independent developer and opensource!
Last I checked, WotC hadn't changed the AD&D ruleset at all.
In fact, they seem to have gone back to embracing those old systems and releasing them again for people to enjoy (which is not something I expected them to do).
And, not to get off topic, but the newest version of D&D (right now called "D&D Next") seems promising. As one person said in his review: D&D Next is like 2nd Edition with a couple of smart things taken from 3rd Edition, but the best thing about it is that it's the first version of D&D in years where the rules don't seem to get in the way. They are planning for it to be modular with a Basic version and an Advanced version.
As far as the Gold-Box engine, there's no reason why it couldn't be revived. No one said that it had to use the AD&D licensing, though with the OGL, it's not like they would need their permission to use the system anyway...just for the settings (Forgotten Realms, Dragonlance, etc).
In fact, if you want to see a game that's being developed using the 3.5 D&D rules via the OGL, but utilizing it's own setting, you don't have to look any further than "Chaos Chronicles," which is what I imagine an updated "Gold-Box" game would look like (in fact, this game looks like a cross between Baldur's Gate with Gold-Box style combat).
Video here: [size=78%]http://www.youtube.com/watch?v=pDhcrgBSM2U[/size]
Information here: [size=78%]http://www.chaos-chronicles.com/[/size]