Bass only first show up in MegaMan 7 and Duo in MegaMan 8 so I don't think that would make sense.
Viewing post in Mega Man: The Sequel Wars - Episode Red comments
It would be awesome for a collection to be made with Mega Man 7, 8, & Bass (aka 8.5). Being able to play as Duo in a game with platforming has been a huge wish of mines for a good while.
Also, the bundle works nicely because those 3 games are the first (and last) of mainline Mega Man using sprites above 8-Bits, because they went retro for 9 & 10 , and 3D for 11 & 12.
The only problem is that, while Wily Wars style is a technical upgrade from the NES visuals, it would be a downgrade for everything except the WiiWare games. In terms of downgrades and backporting, we already have plenty of Mega Man demakes. What can you say? 8-Bit development is easier to work with.