The general point it is really wasn't that gruesome or sexual and Vampires explode in ash so they can be pretty violent with having to use blood. I have seen the TV cuts of Blade movies and it doesn't suffer in transition. Now I prefer an R rating just to give them to the flexibility be more scary or more gruesome. Maybe touch on some content in a more mature way but Blade would be perfectly as PG13 movie as well
Now what could happen is Blade might be first in maybe a "Marvel Knights" line to be followed eventually by say Daredevil, Punisher, Electra, Luke Cage, etc.. Maybe even Deadpool and Wolverine in the future