I think he died way too early. The reason why is because it just seemed that there was more that he had to uncover for himself and had some more unfinished business. For example; back in Code Veronica, he extracted the Veronica virus from Steve and the ending made it look like he was going to do something with it. Not only that, but the same thing happened in RE4 after he retrieved the Las Plagas sample and was going to do some stuff with it.
It just seems like there was more work for him to do before Capcom killed him. Also, what about all those files that explained stuff that wasn't shown in-game? Such as the "Her report" and the faxes and letters he was sending to other people? Since he's dead, I think they should make a game that takes place before RE0 starring Wesker as a playable character. It would explain more about the behind the scenes stuff that was only mentioned in the files. There is way way more mystery to this man that Capcom needs to uncover. Having him dead without follow-up just seems like a cliffhanger in the series.
If they do make a game starring Wesker, here's what it should uncover.
1. Show events that took place between RE2 and Code Veronica. Wesker injected himself and ran away after the mansion exploded, so he was doing stuff between the time frame of those two games while everyone was running around before the nuke hit.
2. Show scenes that explain files that were noted back in the 70's, 80's and so forth. Wesker has files talking about experiments and other stuff that he was doing while he was working alongside Spencer. I think it would be cool if Capcom uncovered some of this mystery and showed some more behind the scenes stuff that Wesker was doing in his younger years.
3. Uncover any other mystery that was left a cliffhanger in the series involving Wesker. I guess they could show some Spencer scenes as well, and the rise of Umbrella.
Capcom, please make this. I would even pay $150 if you threw this in with a survival horror setting.