About Alucard: I would like to see him as a comical character. But without making mock of him. I will explain my point...
In the Lord of the rings movies, the filmmakers transform Gimli into a comic character but making mock of him. They though that, the best way to make someone funny is making him stupid. I don't agree. When I read the original book, the only character that make me laugh is, actually, Gandalf with his brutal honestity. And, after the laughs, I still respect him for his wisdom and power.
Look at "The dark knight". The comic character is Alfred. And he his not a moron, but a very intelligent father figure. Look at "Conan the barbarian". The comic character is Subotai. And he is not a moron, but a very brave warrior.
I always find Alucard funny. Because his old-fashioned elegance, his ludicrous seriousness and his extremely pedantic language. But I still respect him for his ethics, his sword fighting skills, and his inner fight.
If you include a character like the son of Dracula in a movie, the easiest way to represent him is making him a troubled kid with daddy issues triying hard to be cool. You know, the kind of "twilight" character that EVERYBODY hates.
The thing is: a character can be funny AND cool at the same time.
And yes, I would love to see a "Lethal weapon" dynamic between Alucard and Simon. Why not? Long live to the "pulp" light hearted adventure.