Pattinson is way more famous and popular than Hammer. And had success as a leading man (albeit in an already established property). So the idea that he will be compromise between Reeves and the studio is a stretch, unless you mean a compromise in the sense he can he's a very good actor but is still well-known (unlike Hammer).
Reeves is a good director but I doubt Pattinson is dying to work with him, if you've seen the names he's worked with the last 5 years. And even if he likes Reeves concept, I still don't think he'd be enthusiastic about signing onto huge group movies that Reeves won't be directing. If this was like the Dark Knight trilogy I could be see him being interested, but it's not the same, so.