Here's my post for some big questions, in the hopes some dev will have time to answer them. Feel free to add your own everyone!
1- How will the multiplayer work with modding? Anything to prevent cheating or to help with mod-syncing?
2- Will there be Diablo 2-style server-based characters?
3- What will the max party size be?
4- Can we expect an alpha or beta test? This WILL need balance testing after all
5- How big will the game be compared to Torchlight 1? The kind of difference between Diablo 1 and Diablo 2?
6- Will anything be import-able from the first game? Any bonus for people who bought both?
7- What platforms will it be released on?
(Will update as I come up with more questions)