Would they actually attempt a miragul 2.0 to coincide with the heroic character boost to level 100? Could we see a brand new server launch at RoF? It would make a great starting point in my opinion. RoF is considered one of the great modern expansions by a lot of people.
The new heroics aren't in until September. The TLP releases in May. So, no. Also, unless it launches with no truebox, it's garbage.
Chances are less than zero. Miragul was an abject failure. There will undoubtedly be people interested in doing casual progression from 100 as soon as the new Heroics are available, but that can be done easily on a Live server, with no concerns about Truebox restrictions.
I think Ragefire is at RoF according to a sticky, so you can start at that expansion today, no waiting!