I've held off posting in this topic and the similar one at CG Talk as our friend Icecaveman would likely be on my case so I'll try to be balanced and not overtly try to get people to jump ship.
My reading of things is the UV enhancements will be R19 at the very earliest. As far as I know to redo the UV tools and do it properly which I'm sure MAXON will do (there history on redoing modules / tools is excellent) requires the new core. Currently there is no UV edge mode. You can't redo the UV tools properly and not have an edge mode. The problem I see it is there's a lot of work to redo the UV tools. Many people have mentioned other apps that have better UV tools. All those apps have developed their UV tools over a period of years and versions. MAXON essentially needs to deliver all this in one hit as they pretty much need to chuck out the entire UV tool set and start from scratch. The UV Peeler tool can probably be updated to work in with the new UV tools.
What I find interesting or something to ponder on is what's gong to happen with the paint tools? As you saw in the tech preview video, the paint tools in BP are pretty basic. No symmetry painting. The list is endless and virtually every other application has superior painting. What BP has always done well is paint on multiple channels at once and the generated layered files be Photoshop compatible. The paint tools again need chucking out and rewriting from scratch or painting be added as a sub set of the sculpting tools. As I've mentioned here before we had a proof of concept paint tool plugin that was derived from a sculpting tool. That's the direction I suspect MAXON will head down once they get a developer up to speed on the sculpting tools.
So while I'm here, kudos to MAXON for being brave and showing some future technology. That's the kind of communication or some of what I was harping on about last year when I jumped ship. Perhaps next time they do it they just run it past their Beta testers first and get their reaction. If it's positive then release the preview as is or if not, redo it and add a bit more polish.
Re multi view feedback. I can only comment on Modo and in that you can have multiple views. You paint in one view and once the brush stroke is finished it appears in the other views. If you watch the BP video carefully the paint wasn't applied to the second view until after the brush stroke was finished.
Will R18 have the new core. MAXON have pretty much said themselves in their blog that it's coming over the next few versions. It wouldn't surprise me if the core rewrite is actually finished it's just the UV tool rewrite and maybe a material node system being added is holding things up. To give you the new core with faster object handling they have to give you the new UV tools. Time will tell and we're only a few weeks away from R18 being announced.
Cheers
Nigel