It won't be a regeneration an episode that was filmed for the first half of the season has been moved to the second half, which indicates no one's likely going anywhere. Matt Smith also indicated in an interview earlier this week that he'd been told the title of the 2011 Christmas special, which doesn't mean he's in it, of course. The utter lack of any rumors/leaks/etc also suggests no regeneration in the offing. Then again, they were able to keep Catherine Tate's appearance in Doomsday an utter secret until broadcast, ditto Billie Piper's appearance in Partners in Crime...
Easter is late this year (later than it's been in years) but the BBC is still saying Easter for the debut time. The Saturday before Easter is April 23, so that's where my money remains.
One piece of information that I've only seen in one source - the newsletter of the Canadian Doctor Who fan club The Doctor Who Information Network - is that the split season format is going to be a permanent change. I think it's premature to say that, since for all we know we may be about to encounter our generation's equivalent of when Doctor Who moved from 25-minute, 26-episode seasons to a 13-episode, 45-minute-episode season in the 1980s, which bombed. Plus, as stated above, this was a story-driven decision requested by Moffat, not imposed by the network (which was the case back in the 80s). However with the BBC's ongoing financial woes, shorter seasons might be one way to keep the show on the air if push comes to shove. Look at most British series - Red Dwarf, the original Office, Hustle, etc. and the length of Doctor Who's season is actually pretty long (ditto Merlin). The first season of Moffat's Sherlock ran a whopping 3 episodes.
There's also the question as to whether the 7 episodes that air this spring will be Season 6 and the remainder airing in the all will be Season 7. Moffat has already referred to the second half as Season 7 in a few interviews. But just as the BBC officially started the numbering over again with Matt Smith (i.e. Season 5 was actually Series 1 again), only to retain "Fifth Series" for the DVD/Blu-ra release, it may take a while before the official season numbering to settle down.
Alex
