I've just spent a bit of time looking at historical numbers for game sales relative to preorders at time of release in North America. And I've noticed something - for home console games that aren't hugely-anticipated (that is, with preorders comfortably in the hundreds of thousands), typically North American sales tend to be about 10x the preorder numbers (note: there are exceptions, such as Beyond: Two Souls; also, 10x is a rough number - 7x and 14x are both close to 10x). Some examples:
From 2013 (note that many of these continue to sell):
Super Mario 3D World, preorder 97k, LTD 980k
Skylanders Swap Force Wii, preorder 104k, LTD 980k
Skylanders Swap Force 360, preorder 57k, LTD 640k
Wind Waker HD, preorder 78k, LTD 580k
FIFA 14 PS3, preorder 69k, LTD 660k
From 2012 (note - Wii U launch not counted, as that's a special case):
Epic Mickey 2 Wii, preorder 57k, LTD 590k
Epic Mickey 2 360, preorder 27k, LTD 270k
Forza Horizon, preorder 86k, LTD 730k
Dishonored 360, preorder 80k, LTD 980k
Dishonored PS3, preorder 60k, LTD 620k
From earlier:
Sonic Generations 360, preorder 63k, LTD 590k
Sonic Generations PS3, preorder 48k, LTD 470k
Call of Duty: Black Ops Wii, preorder 62k, LTD 780k
Darksiders 360, preorder 83k, LTD 650k
Silent Hill Shattered Memories Wii, preorder 27k, LTD 220k
The Saboteur 360, preorder 20k, LTD 240k
Resident Evil Darkside Chronicles, preorder 34k, LTD 450k
Brutal Legends 360, preorder 64k, LTD 600k
and most importantly:
Bayonetta 360, preorder 35k, LTD 490k
Bayonetta PS3, preorder 33k, LTD 410k
Note that you do get some interesting fluctuations in this effect. Mostly, this is due to a title not living up to hype, but sometimes you get a case like Goldeneye 007 Wii (52k -> 820k), Sonic Colors Wii (45k -> 870k), Borderlands 360 (67k -> 2260k) or Mass Effect 2 PS3 (22k -> 750k). But it seems like titles with moderate hype, that aren't overhyped, tend to sell somewhere in the range of 10x their preorder numbers... and Bayonetta has followed this pattern.
Which is where I now bring in Bayonetta 2. At present, preorder numbers stand at 39k, with 13 weeks until release. The sharpest buildup of preorders tends to happen in the last few weeks before release (7 weeks before release of the original Bayonetta, it stood at 11k on 360 and 13k on PS3 - it more than tripled on 360 and not much less than that on PS3 before release). So it's quite plausible that it could get to 60-80k before release.
But even if we assume that no more preorders come in, and we assume 10x, then in North America, Bayonetta 2 would sell 390k, around what Bayonetta sold in NA on the PS3. Bayonetta PS3 sold 1.14 million copies worldwide.
This doesn't prove that it's going to do well, of course. But it's certainly encouraging.
