I think there were a few issues with Detox...
Dre first is a producer and his next project after 2001 had to be another shift in his sonic sound. His shift actually came in his 50 era - where he was using his now notorious neo soul esque swinging drums (although much harder) and epic instrumentation (huge strings, heavy, slick bass, penetrating synths, clean yet prickly guitars) with powerful but simple melodies. This is when he should have dropped the next album. Sadly, he took too long, that sound died out, and he was stuck making songs sounding like his 2005-2008 during all his Detox sessions. All the leaks sounded dated, and not really evolved from his 50 era.
Secondly he most likely lacked inspiration which meant he lacked direction. 2001 he had to come back and show he was the best again - had em with his, a revitalised snoop, and a reason to show he is the best producer around. His hunger probably diminished over time.
Why I think 'Compton' makes sense to him is that it was easy to get inspired again. Compton I guess is a mindset, which is easy to resonate with. Using the movie as a reference (and something that probably took him back and invigorated him), he can stick to creating a sound that he thinks best reflects his city and that mindset - for the old skool and new skool.
I think this album will be nothing short of amazing in terms of sonics, which is what I look for in Dre projects.
The best rumour I ever heard about Detox was that it was supposed to be a hip hop opera..with different rappers being different characters and having different narratives. If this is the concept for the new album..
but i doubt it..