MJ should have mostly stayed away from the electronic "futuristic" sounding music on this album. Everyone was doing that sort of music at the time due to the new millennium starting. He should have aimed to have plenty of organic, raw-sounding songs with live instruments on the album to stand out from everyone else.
Tbh, thinking about it more, it was fine for MJ to want the album to sound very digital and futuristic. Yeah, everyone else was making music like that at the time, but MJ was always a trend chaser to begin with. The issue is that aside from "Unbreakable", all of the futuristic songs that ended up on
Invincible sounded a little more pop than legitimate R&B; "Heartbreaker", Invincible", "Privacy", "Threatened" and "2000 Watts" all sound like 'N Sync or Britney Spears songs. It's a shame because Darkchild and Teddy Riley made some decent futuristic R&B and hip-hop songs at the time, but for whatever reason, they didn't exactly do that for MJ.
Maybe the Neptunes could have done a better job, but as we all know, either MJ or his manager turned down all of the tracks that they made for him. He probably didn't want those songs because they sounded too much like
Off the Wall; according to Pharrell, MJ wanted something more like "Superthug" by Noreaga, but the Neptunes didn't accept his request for whatever reason and the collaboration never came to be. MJ apparently wanted to work with Dr. Dre, but got turned down because Dre preferred to work with lesser-known artists. In that case, I think Timbaland would have delivered the kind of futuristic sound that MJ was looking for without coming across as cookie-cutter pop. Darkchild clearly emulated Timbaland's style on "Heartbreaker", as well as "Anybody" for Brandy, and it's better to work with the real thing than a copycat. I don't think Timbaland would have been willing to fully commit himself to MJ's album like Darkchild and Teddy Riley were, though, so maybe it wouldn't have worked out.
In any case, MJ would need to rely on his own team like Brad Buxer to put out truly great music, not chase trends with whoever the most contemporary producers were at the time. Even for upbeat songs, MJ was capable of making better music with his own team than with others. "Hollywood Tonight", for one, would have certainly become a classic MJ song if it was finished.