Why would you want a 12 over a 7? ... Seven is the right knife for any job.
I think the 7 is a great knife and a great choice for an all-around knife. I'll also add that I'm with C_Tanner and you really shouldn't be caught with one knife, but sh!t happens so let's say you're gonna pick line up the 7 and 12. If you're stuck in a survival situation with just the 7 or just the 12, I think they're both capable of keeping you alive and getting you out. I was deciding between those two and it was a very close call. Almost all of my research was based on Beckerhead comments on this site and from Doug Ritter's page that explains how he came up with the 12. And I'll admit that I have not been out in the field with either of these and while I have spent plenty of time in the woods, I know I'm not the most experienced hunter, woodsman, bushcrafter or survivalist so I'm not asserting any of this from experience, just my own research into the wealth of knowledge in this subforum and for discussion sake.
So the clip point will probably make some aspects of field dressing game a little easier with the 7 but you should be able to get field dressing done with the 12. It didn't seem like the 7 would be a lot better or even much better so maybe we can leave it at the 7 is just better. The 12 does have a nice point though and the less pointy and slightly smaller 12 ought to be a little more manageable and better at some aspects of field dressing than the 7 too, right? Seems like this area we could call a draw and at best, the 7 is marginally better.
Is there some sort of bushcrafting that the marginally more pointy 7 will excel over the 12? I'm not sure. Maybe someone can point this out for me but it seems like a draw here too.
So what about the reason why so many people seem to get Beckers? Chopping and batoning. The extra inch on the 7 might allow you to baton or chop a little bigger piece but the clip point will mess up your baton before the drop point. And isn't it reasonable to think that the extra inch in that clip point will be a little weaker than the drop point? There's less metal there so it seems possible. I think the 12 might come out ahead here.
The other thing that appealed to me was the collaboration aspect. I don't have any other Rowen knives but the it seems they're well regarded around here so that seems like a plus. Doesn't the smaller run imply a little more attention to detail and quality control? I think that's a plus for the 12. There could be a risk that none of the designers ended up happy and there's too much compromise but I didn't get that impression from what I read. I think Doug explains he started with the 7 and carved the 12 out of that. I know he does the knife rights stuff but the survival stuff is his thing, right? He is very focused and informed on the one-knife do-it-all utilitarian scenario. So while the 7 is a combat knife and would be the better choice if you may find yourself in a knife fight or fighting bears, the 12 is probably the only Becker that was purely intended for the survival scenario.