Do you think there will be AOSP roms like CM12 until december 2014? I think it will take more time to develope AOSP roms for Lollipop.
I was just going on past trends. It took CM over a month last year to release their first nightly for CM11 after Kit Kat was released to AOSP. I expect to see a relatively comparable release time with CM12. It could take longer, but I'd be surprised if you didn't see CM12 for many devices before the years end. Remember, Cyanogenmod in bed with OnePlus and have promised timely updates. That effort will trickle down to everyone else.