I'd say his musical legacy is in fantastic shape. Despite everything his music is still selling, being streamed and played on radio. He's still doing extremely well in the US despite all the negative stories and music in general selling less. He has very steady catalogue sales there. Number Ones is doing very well worldwide.
I hope to see Dangerous be celebrated in some way at some stage. The Off The Wall documentary and re-release helped OTW see steady catalogue sales in the US. I'd love to see Dangerous follow in a similar vein.
I always feel Number Ones came at the exact right time -2003- and reminded people how great the tunes were. Went to #1 in the UK and #6 on Billboards R&B album charts, #13 on Pop charts. It's a shame that the video for One More Chance was never completed for it -for obvious reasons- but I also loved The One special which also had a DVD release which surprisingly cut a section featuring The Way You Make Me Feel which was part of the TV airing. Then there was Number Ones DVD also.
There was actually a consistent amount of releases in the Noughties with The Ultimate Collection including Dangerous Tour Bucharest the following year and the Japanese version came with 5 extra tracks. Also a re-release of Moonwalker.
2005 saw the release of The Essential which hit the #2 spot in the UK. They would release a limited edition of it in 2008 with a 3rd disc and it became a posthumous #1 in Australia, Finland, Ireland, UK and Mexico and hitting the top-5 in many countries in 2009.
2006 came Visonary The Video Singles; 15 of the DualDisc singles hit the #1 spot in Spain with the other 5 singles peaking at #2.
2008 was a great year with MJ looking healthy and back in the studio. Thriller 25 featuring re-worked Thriller hits with Will-I-am, Alon, Kanye and Fergie which sort of set a new trend for MJ. In America some stores stocked their own exclusive editions; Best Buy: Thriller 1982 Def Remix, Circuit City: WBSS 1982 Dance Mix, Independent Music Stores: Billie Jean 1982 Radio Edit Remix and Target: Billie Jean 1982 Club Remix, while Amazon and ITunes -USA only- included Billie Jean Underground Mix and Thrille Instrumental. Walmart did a Deluxe fan pack packaging Thriller 25 and the Number Ones DVD together. It debuted at #2 on the Billboard albums chart. #1 on the Billboard Pop & R&B/Hip Hop Catalogue albums chart 11 and 16 weeks respectively and peaked at #3 in the UK. Posthumously it made #1 Czech Republic, Mexico, Portugal and Switzerland.
2008 also saw my personal favourite Hits Collection 'King Of Pop! Released to celebrate MJ's 50th. Peaked at #3 in the UK matching Thriller25 in same year. Love the 3-Disc UK Deluxe Edition and also the 3-Disc French Fan Selection.
The Collection was released in 2009; 5-album box set which strangely omitted HIStory and Blood On The Dance Floor. This box set did ok in some parts of Europe; within the top-5 in a few places.
Motown also released The Stripped Mixes/ The Motown 50 Mixes and the beautiful Hello World: The Complete Motown Solo Collection.
Will have to get into all of the posthumous projects and discuss their impact and what they've done in terms of bringing new fans on board and old fans back.