Nostalrius Begins - Quality wow vanilla realm (1.12)

When can we expect TBC to be released if developers continue with this tempo?

If server actually follows the current timeline, TBC would probably release in late 2016 - early 2017. Though I guess it'll take longer than that, many dates in timeline are "to be confirmed"

It's not coming out for quite some time. At least a year out, if not, more.

Hey Dad what am I getting for Christmas 2020?

It'll be a race between CC and nost to release first, if you catch my drift?

When naxx is cleared is when they will be working on TBC. So 2020, which is a few years shy from CC which will be coming out in 2025

The truth is that we have no clue of when a Nost TBC server would be. If they follow the timeline reasonably well, then it would probably be late 2016 to early 2017 as others have said, but there is also the part of coding and making ready such a server and that could take a while.
My own personal guess, which should by no means be taken to seriously is early 2018.

I doubt if would be earlier than 2018, if at all. There is a reason why CC release gets pushed back all the time - publically available MangosOne codebase is pretty broken. On top of that, those guys are redesigning whole mangos architecture in order to get perfect result (loot table system for example).