Killed Blade but birthed Deadpool
The fact is that without this movie we wouldn't have Deadpool.
I just saw the Google Talk Ryan Reynolds interview where he says that he didn't even know who Deadpool was until someone from Marvel saw Blade Trinity and sent him all the comics saying he was Deadpool in that film. Ryan says he instantly fell in love reading the material. So, no Blade Trinity NO Deadpool.
Good for Fox but bad for New Line Cinema who made Trinity. New Line basically turned out to be the farm system for Fox in this case. Develop the young talent but cut the player. Then, the player signs with another team and is the MVP of the World Series.