They need to decide wether they are going to roll the dice and make more than 3 movies, or make just 3 movies. If they are going to make 3 movies only I think Blade needs to run into the Grandmaster of all Vampires, like the guy tycho is talking about. Someone who is just super-bad. I mean the man who first got the vampire "cancer" in his blood. I would love to see Blade have to travel to an OLD OLD city like setting. Where the super-bad vampire dwells. I think it would be neat if this vampire did not surraond himself by technology, but used old Vampire stuff. Maybe see a vampire that has a very old army to use as a defense screen. I don't know. I would just like to see Blade end it in part 3. Maybe he can try to find something that the super cool Vampire has been hiding for thousands of years that he knows can be his downfall.
Or there could be a super-bad Vampire that shows himself and thousands of years and masses the ranks of vampires up for an end all be all war with Blade.
The possiblities are endless here.