I don't think 2.7 Invasion will be the Makeb sized expansion, BUT will be the precursor to it, just because their not hyping it very much. I expect that the big expansion will be for purchase, much like ROTHC was, but similarly priced. Because not much hype yet, I think the timeline is still towards the end of the year.
Also, don't forget that we still have upcoming rakghoul events on Tat and Corellia i believe. Last but not least, wasn't there supposed to be another Gree event with new drops? Call me pollyanna, but I hope the devs are working to tie all this together into the new expansion...maybe something like the rakghoul plague is so ravenous the Gree want to investigate, both the Empire and Republic think the other faction released the plague as some kind of chemical warfare and need to kick of the war again by invading each others academies...(ok i'm back to reality now)