Did the Exile team move on to other games (as hinted earlier) or something else?
So the SG/Exile team is making non-FS games now (guessing from not-Mod, not-FS)?
Yes, we're working on a standalone game. I don't want to reveal any details yet, so let's just say it's gonna be huge and overambitious like our previous projects, with lots of assets and rich, multi-layer storyline. It will take some inspirations from both Freespace and our mods, but as it will go commercial, we will try to be more mature and less controversial in narration

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Probably you should've made SG and Exile just standalone projects instead of chapter based things.
Probably true, but when we invent a storyline, in the end it's always far too long to fit in a single campaign

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On the other hand both SG1 and Exile 1 can be stand alone campaigns. just with open endings

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But are they willing to work on Exile in the future? I mean, making something like Exile takes years, the missions alone, and with just 2 people it seems almost impossible. BTW, has anything been done yet aside a semi-complete design doc, and are Acts 2-4 of the same length as Act I?
Well, the problem with Freespace mods is that you have to put lots of effort working on obsolete and... a bit rough tools like Fred and non-trivial game mechanics requires making hacks to make it work because Fred was simply not designed for them. Checkpoints, dialog systems, achievements... A good example can be Dirty Job mission that required tons of copy-pasted sexps managing interactions between each drone and each asteroid (so 10*20=200 sexps). Sexps that I had to modify in notepad many times when I fixed something in drones' behaviour. Of course if I did this mission from scratch today, I'd use LUA, but still... Now I'm working in Unity on our own game and there's so much more possibilities that it'd be hard to return to modding Freespace. And last but not least - own game can be commercialized, and a mod can't.
Nothing serious was done for Exile 2. Nyx already told you about some assets he did, he also made bases for 2-3 missions, but nothing more.
Act 2 was planned to have 25 missions. Acts 3 and 4 were not planned in details, but probably they'd be of similar length too.