This is the only thing about announcements that really ticks me off. She hasn't come back, and no matter how much people like her, the chances of her coming back are really slim. Actually try and think about who the real "antagonist" is going to be (I put that in quotes because, well, we don't know the intentions of said antagonist).
At this point, with character information at an end for now and Sunday on the horizon, all I'm hoping is that my story predictions were right. Then again, a lot of people probably share my thoughts, so... yeah. ^^;
maybe she won't come back, maybe she never left. (most people forget this other possibility, but ZUN's not telling anyone which of them is true, at least for now.)
figuring out antagonists for the TH games would require some large amounts of luck and knowledge on japanese culture, history, etc.. too much information to derive possibilities from, imho.
I'll disagree with you, though, in that I hope (pun not intended) that the gameplay is solid, fun and competition-friendly, beforehand.
My weird pattern figuring sense says that, as an after thought, HM "has" the "mission" of surpassing the low expectation caused by it being based on Astra Fighters, while DDC also "has" the "mission" of being more interesting, gameplay-wise, than TD. (like KoF XIII had to fight against the backlash its predecessor caused) /TD "bashing"
random thought of today (this one I had for a while, it's not related to or dependent on the release of new games): since it's a possibility (read well, *possibility*) that Mima can (as well as can not) be the shrine's ("evil") deity, it *can* actually make sense, as it's said (not in the touhou canon) that vengeful spirits's (onryo) anger can be placated by turning said spirits into deities. Though even Mima's PoDD profile (which, being PC-98, means little to the current Touhou canon) mentions that her evilness has fallen off from her due to having lived for a long time.
About her goal to become a deity.. one day I looked into a video of her translated ending in MS (and Yuka's), and
By the way, I'll main Byakuren (if the game turns out to be good), and sub other people (wishfully thinking that Koishi is OP, so that I can pretend to be playing as DotS' Koishi)