I'm going to go with something in between; it's WH40K as they've always *wanted* it to be played; huge, epic battles, with crazy high-powered stuff kept in check mainly by fluff and a sense of sportsmanship. It's just that it would be impossible to convert regular 40k to run that way, so they decided to tackle three birds with one stone; re-tool the rules, explore this mythic period of the lore, and make all the shiny crack for the flagship faction.
When they finally get the Heresy rounded off, what they need to do is the Rhana Dandra, let the Eldar take front and center for a time (also Orks and Necrons, depending on who wants to be petty enough to take advantage of the end of everything to settle some old scores).