Soldato
If I'm honest, be very surprised if CTF was introduced, it doesn't really exist in TF2 these days (apart from Turbine).
The game itself has already created a sort of "must have classes" to win aka. meta, if you go against those you will quickly lose.
Hopefully they can make some changes and make it a little bit more varied (as they originally planned).
I'm hoping they make it so you can only have 1 character per team (as in you can't all be the same one).