I liked Black Dynamite, but there weren't enough "movie-making" gags, like the scene where he could see the boom mic, or the scene where they had to replace an actor because he actually got hit in the fight scene. The second half of the movie was almost all blacksploitation parody, which is always good, but it inevitably suffers from the comparison to I'm Gonna Git You, Sucka, the greatest blacksploitation parody of all time.
I liked it, but I thought there weren't enough jokes period. A lot of time went by between gags of any kind, IMO. Other parody movies like the Naked Gun series and "git you sucka" did a lot better job of keeping the plot moving while still inserting one-liners, sight-gags, etc to keep things funny.
I would be SO with you on this one...if it was Wally West. But it's looking like the film wants to go with Barry Allen, so Rosenbaum wouldn't necessarily work. And hell yes, I would also be on board with Mos Def as John Stewart.