If you remember at the time it was off of Snipes name what brought people to see the first Blade movie, not too many people knew who Blade was from the comic books. It was Snipes who gave Blade his Bladeness (The Look), designing the weapons, and bring in his fight/stunt team for great action scenes. As well as putting the directors and writers in check stating Blade wouldn't do certain things that was in the script. In the first Blade script Blade was supposed to cry when he see's his mom. In Blade II it was written in the script that Blade kill the vampire embryos in the test tube beakers. Snipes said that's something Blade would not do, so they showed Whistler doing it. So Snipes contributions now get overlooked and get overshadowed.
Snipes a producer of the films was not allowed the same creative input he had during Blade 1 & 2 as it shows. Wesley is a method actor. Once tension arouse, suddenly Wesley was "difficult" to work with, even though he was method acting in the first two films. It wasn't a problem because both those movies were good.
The original script theme he signed on for was changed behind his back. He felt he was being used as the fall guy to start a Nightstalkers spin off franchise (In which he was). You have Goyer and Ryan Reynolds changing the script on the fly thinking they are making it more funny but making it even more corny. The original story was supposed to take place years later after Blade 2, with the humans already being enslaved by the vampires. No Dracula. It was in their best interest to listen to Wesley because the Nightstalker movie got scrapped and the Blade tv show flopped without him.
Snipes had become friends with Goyer and starred in his film Zig Zag because he believed they had a mutual understanding about what they wanted to do for the next Blade film. The studio didn't want Goyer to direct Blade Trinity because he did not have directing experience at the time. Wesley helped get Zig Zag off the ground to help Goyer prove to the studio that he could handle himself in the director's chair. When Blade Trinity wasn't going as planned, Wesley felt betrayed.
If you listen to the audio commentaries on Blade 1 & 2 its like him and Goyer are the best of friends. Goyer has nothing but positive words to say. Then play Trinity's... and it's like Goyer is talking about a totally different person. Always downing Wesley, pointing out every flaw, and every shot where "that's not Wesley that's his stunt double". 8 year friendship out the window.
I used to post in the BladeTrinity.com forums before the movie was released and Snipes would chime in here and there and give his side of story. Since Goyer/NewLine and crew got the media on lock on the situation.
During open question, Wesley warned fans that he would not be doing any interviews to promote the film. (That's when we knew things were really getting bad). He had said something like "I promote movies that I'm in, and unfortunately I'm not in Blade Trinity". He pulled out of all public appearances, comic conventions, and promotions. By watching the film it's almost like Blade is a secondary character.
The scene where Wesley talks down on the Nightstalkers calling them "rookies", is actually off script and how he really felt about the film. He basically badmouthed them in that scene and returned back to his trailer, refusing to do a retake of the actual lines. The scene where Blade neglects to unchain Hannibal King, and heads directly after Dracula is also off script. The scene where Wesley goes back for his sword and says "forgot my sword" is also off script. Yet these are some of the best scenes in the film. Wesley obviously knew how to play the character, yet everyone continued to ignore his input and contributions that worked previously in the first 2 films that were successful.
I'm not defending all Wesley's behavior or how he dealt with the situation. I just wanted to explain some of the reasons behind it. These are just conversations that Wesley had with the fans. His side of the story. Goyer gets all the praises due to his career has exceled doing films like The Dark Knight Trilogy and Man of Steel etc. While Snipes career was on the landlside being blackballed after Trinity with only showing up on DTV/DVD and had tax issues.