Roots was a series, not a movie, and has many historical inaccuracies, despite being an important work. Amistad was sanitized, Spielbergized, and inaccurate, Sankofa isn't a Hollywood film (it's actually an African film, ironic considering your point,) and Glory is about the civil war period.
Basically, what I'm saying is that there isn't as much out there, especially when you're talking good, accurate, well-made media on the history of slavery. It's a wide history, too, so 4 or 5 films doesn't really cut it. Glory's context is very different from Roots, for example.
As for Africa, for me, it's too late for all that. Movies about African history in general are fine, but to tie the ancestry of a mixed up, long-separated group to any particular people in Africa would be reaching. I'm not into all that DNA ancestry testing- it's inaccurate, vague, and relies on false assumptions (should Black folks who have more European than African DNA celebrate that and go visit European villages and learn their languages?) I'm fine with general Black solidarity and African history, but it's not as relevant to me as the more immediate and direct history of slavery, which produced a new people- modern Black Americans.