Let's start with some basics of what could have been better.
1. Dracula isn't a 3k year old vampire. If they wanted to do something like that take an egyptian or mesopotamium deity, and vamp them out. Good choices are Osirus, Set, Anu, Tiamat (ancient female vampire would work well), and Cain. White wolf may throw a hissy fit, but if you create enough distinctions no worries.
2. If you had to have dracula, do some homework. Watching bela legosi at three in the morning eating doritos in underwear doesn't work (and it wasn't even that good). There was absolutely nothing to make him distinctive a big bad euro vampire Vlad Tepesh (who is an awesome character even before vamped). Heck buffy villians are superior in all ways.
3. Do not kill off whistler in the first 5 minutes of the show. He is the consistantly best character, and removing him got rid of a person who could have helped integrate the two generations better. If you need to kill him (again), make it actually useful.
4. The nightstalkers could have worked, but they should have been setup as a scooby like relationship with blade. They needed to at least be integrated in a manner that didn't seem forced. The chick has a hollywood weapon, and the twerp should have actually been useful beyond the first five minutes. Being an ex vampire doesn't cut it (whistler was one, and he's three times the man you'll ever be).
5. The major vampires were bad. It's a sad sign when HHH was one of the best played of the characters (although why they game him a vampire little dog is beyond me). That female character had the worst lines in the show, and created dead silence with her horrible overacting. The other guys weren't too bad but we knew they were fodder.
6. Never got the feeling that the Vamps were using the system against after his capture after the death of whistler. I know for a fact if he killed as many cops as anyone did, he shouldn't have a moments rest throughout the movie.
What would have been kewl is if he finished off the big bad, and the rest of the vampires, tired and exhausted and as he left, found out the building was surrounded by cop cars. Complete with laser dot on forehead from a sniper.
7. Don't care about a mixed cast one way or the other, but make them competant whatever you do.
8. One of the stupiest things is when he turns off the blood bank and walks away. What the heck is stoping her from flipping the switch back on.
9. Personally, I actually didn't mind wes (and his stunt doubles) performance, but they should add more neat stuff to the story show casing blade's abilities.
10. In the first few minutes, vampires finally got my respect, using body suits to go outside. More usage of this by the villians would have gone a long way of making them credible villians. Usage of guns to slow down blade in cross fires would really prep them for a physical fight.