I would rather get a album full of hidden treasures with outakes from the Invincible seesions including the new Cheater version he was working on during that session. The Will.I.Am tracks should be legit, some tracks he worked on with Stevie Wonder should also be but I don't want to hear what's "popular", I want to here what's "good and untouched"...
And don't worry about Lady Gaga, she's obviously lying about opening the O2 concerts and I'm sure 5 years from now people will remember her as just "that crazy blonde bitch".
PS: However, as we all know $ony is all about the money so by putting all these "popular" artist on a Michael Jackson album will be a huge market hit... Not only about the sales but for the younger generation also who might learn a thing or two about the real Michael after hearing: "Oh, Lady Gaga's on Michael's new album... Michael Jackson? Oh, he's that coll guy who did that... *googles Michael Jackson for more info*..."
So yeah, in terms of the musical quality of the album I'd rather have a legit Michael Jackson album with finished outtakes and demos as bonuses. But on the termsof Michael gaining more fans by having the album very advertised by these artist I'd go with that.
My possition is unclear here. I do however wish that Sony doesn't put artists that Michael never met or actually worked on a at least a song. Having a demo like Hollywood Tonight and just putting Lady Gaga sing two more verses sounds like complete and utter bullshit.
PPS: I changed my mind. I just want Michael Jackson... like MICHAEL JACKSON. Songs he really him, that he really recoreded them, finished and the unfinished demos to be either bonuses or just do something clever with them like Alec said. My brain hurts if I use the names "Lady Gaga/Justin Bieber/Kesha/etc" and "Michael Jackson" in the same context!