Hey, I like that idea. When playing the game for the first time, it appears Barry is up to something, we find out later Wesker was threatening his wife and 2 daughters.
To touch up on your idea, Umbrella Chronicles (Wii, or PSN download) actually has you play as Wesker during the lab explosion. Him escaping and surviving.
It also goes further in Rebecca Chambers and Richard Aiken's story. You play as the both of them and you fight Yawn, the big snake, the snake Richard got poisoned with and you had to get the serum to save him.
To play as Wesker and Barry in original Resident Evil form would be a cool DLC. Anything that goes deeper into story-line and lets us play is definitely worth it.
Well, just in case you or someone else doesn't know about Umbrella Chronicles or even Darkside Chronicles, there super fun games that add a little bit extra of story, especially Feb. 2003, Russia. The end of Umbrella. Its super fun.
And 2002, Leon and Krauser working together in South America. Also, Ada Wong escaping during Resident Evil 2, and Hunk, the 4th survivor campaign. : )