They are as we know adding more of the game elements into the sequel this time round, so why coudln`t they do that the first time round, i think this may be better than the original which i detest more than any other movie i`ve seen.
To answer the question as to if Wesker will be in it ? maybe at the end of it, and in the third one yes but i think they`ll leave him out untill the end and have him appear in the climax of the film, or will they ?.
He better be good in it as well, as he`s one of the better characters in the games (when we see him that is).