I've only read 'bits and pieces' of this thread (so what I say may have been said by others), so...
1. There is NO QUESTION (IMHO) that this is meant to attract people to visit. This isn't just to give people something to do. In their minds there is already something for you to do.... buy food, beverages, and plush. They wouldn't spend $$$ on a long show in a nice looking theatre that uses precious executive parking unless it was meant to attract visits.
2. This seems like the best thing to have been announced at D23 (and this is coming from someone who doesn't find these kind of shows interesting). A quality offering that provides a genuine need that doesn't displace another attraction. If they follow through with this*, it makes you feel good even if you don't personally enjoy it. It's very presence adds class & quality.
3. My guess is that the bypass from Center St to Tony's will become permanently open, where the theatre will end up. I'm guessing the north part will remain a bypass.
4. I'm guessing as well that 'New Street' won't simply house the theatre. If they can fit retail back there (even if it's kiosks) it will be there.
* - Wall Street (unlike in the past) wants stuff added in the parks, so it makes the D23 stuff much more likely to happen then stuff that ended up in coffee table books. Worst case scenario would be if *new research* tells them that it won't drive additional attendance and in fact gives people less store time (which might cause them to 'Hyperian Wharf' the project).