Yes, there is a next-generation Area 51 on the drawing board (code name: Area 52).
But it is still really early in the design phase, so there's not really much to say about it, except that this is a significant redesign and overhaul of the process, and not a simple fix-it-up type project. I wish I could indulge you in premature, wild speculation, but the design is still developing and changes just about every day. Besides, too much peeking under the covers takes all the fun out of a big launch!
The ETA for this is still way too early to say… but its almost certainly in the months time frame. It's not going to be weeks; it's not going to be years. In actuality, you'll likely have plenty of time to "kick the tire" as we test bits and pieces of this before it entirely replaces our current process.
For anyone wondering about their existing proposals, I would just continue as normal. When this new process finally launches, it will quite literally put anyone with a proposal so far and ahead of where they are now, no one could possible feel like we've set them back at all. Even if its not ultimately the current Area 51 process that launches your site, you are still gathering ideas, building consensus, and finding an audience to help build your site. This doesn't change any of that.