I think Capcom did exactly that with RE5, I expected to hear about the mysterious Organization/Agency that him, Ada & Krauser all worked for, but there was not even a single referrence to it, indirect or otherwise. They also neglected to talk about the even more mysterious "S". They could have even mentioned the HCF thing that was on the back of Wesker's outfit in CVX(in a picture anyway).
And to be honest I wouldn't want them to mention Wesker in RE6 or anything, maybe other than mentioning his name or making a referrence to him, much like Leon was mentioned by Claire in CVX & Chris in RE5, despite being nowhere in either game. But I wouldn't want Wesker to return in RE6(or at all), and I think a nice way to answer some questions would be to close the lid on that topic, especially since we are going to have to wait 6 or however many years for it...