Wow, this is very interesting. I think some of the planned features address some of the complaints about Mint 14, like the fragmentation of settings between Gnome Settings and Cinnamon Settings and Cinnamon 2D being slow on older machines (which are the ones which need to run Cinnamon 2D). I'm excited about desklets and the applet/theme installation from Cinnamon Settings. I'd also love to see Cinnamon 2D use OpenBox (not sure of the actual benefit, but it would be really cool).
I'd like to see the software manager become visually similar to the Ubuntu Software Center and the Deepin Software Center, although I don't want it to put on too much extra weight.
I think it would be interesting for the live-installer to get new features and a face lift, similar to what SolusOS is doing (
http://solusos.com/blog/2012/11/personal-update/), as they use live-installer also. It is long overdue for both a face lift and new features (although I find it very nice right now - it is simple and functional). EFI support is important.
DDM will (hopefully) be added in Mint 15. Hopefully by then it will support hybrid graphics cards.
Personally, I doubt the "from-scratch" thing is particularly significant. I think they will basically be looking into other options, but I don't think they're ready to make any massive changes - they seem to be trying to focus a little bit more, rather than adding new projects. They've dropped Ubuntu-based FluxBox and LXDE, and LMDE Xfce, so I doubt they're trying to add too much work. I'd be really interested in what they found, though, and if another package manager was superior in their opinion (although I haven't found one). I'd love to see an Arch-based Mint though (probably never going to happen, but I can dream

).
Dell XPS 15 l502x - Debian Testing 64-bit NetInst Xfce, SolydX 64-bit Debian Testing, SolydK 64-bit SolydXK Testing
Old Gateway Pentium 4 Desktop - Arch Linux 64-bit Xfce and SolydX 32-bit Sid