I mean this is the first time I've seen anyone classify Revelations as a mainline entry. I don't consider that the case at all. And I also don't think Capcom themselves would be interested in that debate either. All I know is that Revelations exist as side stories separate from the numbered entries, who not only tend to be direct sequels to their predecessors, but also carry much higher production values with them. They are the big Resident Evil games, and in that regard Jill is way overdue to star in one of them.
Edit: I thought Revelations was a lot older than it was.
Even if I'd agree with you on Rev 1, that's still a 12 year old game. No matter how you slice it, Jill is overdue for a lead role.