if they had an album of releasable new music it would have been out by now. there have been a ton of outtakes from the last 10 years leaked, and none of them are any good, all as crap as invincible
there have however been a load of decent quality outtakes from thriller etc. thriller 25 was an awful release, so maybe they could make amends by doing something like the marvin gaye 2cd reissues with a 2 disc ultimate edition with the full original album, plus b sides, 12"s and outtakes from the sessions. so the full version of lady in my life, the unedited versions from bad, and the full length versions of stuff like starlight. no god damn awful new remixes (although some of the new marvin mixes were excellent and in keeping with the original tapes)
the sessions from the last 10 years that have been leaked (ie. from seven) could be wrapped up along with a 2cd version of invincible
there were stories that he had 100s of unreleased songs tucked away, and instrumental albums etc, but then again there were stories that he slept in an oxygene chamber, owned elephant man bones and molested children, so who can tell if this is true. with all the money he owed, and the potential money that could have been made with a well timed quick release after his death, surely they would have put out something other than "this is it" if they had something of interest. motown put out a whole bunch of stuff from stripped to remixes etc to cash in