Wesley is Blade, and what people seem to be forgetting is that besides the charisma his real life martial arts skills also helped make the character.
A lot of Snipes contributions to the character goes under the radar. He designed the weapons, created the sword spikes anti-theft system on it. He created a certain fighting style just for Blade it's not just simple martial arts system. It's more street-base and is mentioned as being jailhouse rock. Then he brought in his fight/stunt team to bring in that raw fight choreography. He also would keep David Goyer in check with some of his writing on Blade 1 & 2. For example in the first Blade movie, Blade was supposed to cry when he saw his mother as an adult. In Blade 2 it was written that Blade would shoot up them Reaper embryos. Snipes said that's something Blade wouldn't do. Even if you look at the comics they rebooted the comics more to Snipes portrayal of character when the movies got successful.
I'm sure Ali will do fine, but I think they should get some black fight/stunt coordinators because Blade shouldn't be moving around like he's from Asia. He should be moving around like a brother. That's definitely one of the main things Snipes stressed when doing these fight scenes.