Interesting topic!
I'll leave the more technical aspects to others, but I'd guess the main advantages are lower power requirements, and lower noise, as you pointed out.
I think AES is an XLR-type digital connector, if I read my USBpre2 correctly. I've never had anything that used it so haven't thought about it much.
Neumann has a similar product line out there now, I believe. Based on what BLee's rig came with cap-wise, the Schoeps one can use all existing Schoeps caps (he has 41s and 22s I believe)
My immediate view is that lots of people will be "against" this technology because it doesn't offer the natural, more analog sound we all know and love. And I believe you're right that it would take away the ability we all have to "customize" the sound of our mics using different pres and A/D converters. Of course, as with past technological leaps, these objections will likely be supplanted by a combination of convenience and by technological fixes that mimic what we liked about the old tech (for example, you can already mess around with tools in Izotope or Audition to mimic some of the sonic characteristics of different pres. I know page has worked pretty hard, for example, to find software methods to mimic the sound of the Sax).
At least insofar as BLee's rig is concerned, I think the most annoying thing would be having the bodies set to one sampling rate. But then, if you are running that type of rig, running out of disk space due to using 24/96 shouldn't be your main concern.
And while the iPad control is cool, not sure I want to add an $800, breakable, stealable iPad to an already high-cost mix. OK, I mean, I would, but it is another thing to "carry around" if you go that route.
I would imagine the transition will be slow as long as the cost differentials are high. If anything, it might drive the price of analog bodies down a bit in the used market.