Umbrella Chronciles had the right idea showing us his activities during RE1 and RE0. But they need to do an entire game just about Wesker and what he was upto in the background spanning over the entire series. So it needs to include RE0, RE1, RECV and RE5. I think that would be pretty epic myself.
there is a way, I thought the same thing after resident evil 1. His death in that game was a symbol for how you can't control what the t-virus does. Expect anything. When he came back it got very predictable.