Dang skippy! Lol...
Djimon Honsou - Yeah, if he's not BP (and he shouldn't be) he basically "has" to be T'Chaka. He brings credibility to the whole production, imho, as an actual experienced Panther (voicework) and a long time fancast to satisfy the fanboys. And people know who he is, so they'll be glad to see him on screen.
Jason Isaacs - Excellent! I was thinking about a bigger name villain character actor, and he's not afraid of comic book movies to boot! I like it! (Side Note: One day, I want to see all these typecast villains team up and be good guys, Hugo Weaving, Mark Strong, all those guys)
Adewale Akinnuoye-Agbaje - Honestly, this guy can do anything. I don't think I'd want to see him as Killmonger, not sure why though. I guess I'll think about this. AAA needs a part in the franchise though.
Alan Tudyk - Oh my, that's pretty perfect. I think Ross works as the connection to the rest of the world, with the typical Nick Fury meeting as the connection to the MCU part of it. I personally thought someone younger for Ross, like a Shia Lebouf (minus the spasticness) or a Zac Efron (but a better actor).
A couple of my thoughts:
T'Chaka - Djimon Honsou
M'Baka - Terry Crews, use his comedic timing to make the villain a bit demented
Romonda (T'Challa's Step mom) - CCH Pounder
Shuri (T'Challa's Sister) - Keke Palmer, young enough to need direction
Nakia (Dora Milaje/Love Interest) - Kerry Washington, voiced Shuri in the cartoon, and has definitely got her African accent down... and she's gorgeous
And... for Klaw's mercs, though story may be too crowded for that, they're basically just stuntmen with acting experience, so tone them all down from comic book costumes and powers to skilled people in Klaw's employ:
Batroc the Leaper -> Georges Batroc (Bodyguard/Assassin): Cyril Raffeili (District 13)
Black Knight -> Father Augustine De Lac (Priest w/Concealed Blade): Ray Park
Rhino -> Aleksi Systevich (RHINO Loader operator): Vladimir Kozlov
Radioactive Man -> Igor Stanchek (Nuclear Physicist): ... drawing a blank. Anybody who can do a Russian accent...
Also, maybe not right for T'Challa, but someone overdue for a breakout role:
Anthony Mackie, 33, (Real Steel, Adjustment Bureau, Hurt Locker, Eagle Eye... 8 Mile)