I am seeing what will actually happen. I'm not ready yet to switch to a new basegame. I'm still having fun with this version. Sure, not everything is what I want but mostly, I'm happy. I'm playing the game now, not in 2014.
There are ways in which TS5 might interest me. I've mentioned them in other threads. I don't just want a reboot of a previous version though even though I enjoyed those. I'm not sure that the player base wants the same things, so pleasing everyone is difficult. I don't think it would be easier in TS5. Eventually, that will probably make sense, but I'm not thinking about it now, if at all.
In particular, if it is targeted at young teens, it probably won't really be for me. At this point, I think there are a few different elements to the player base, some of which are quite different from each other.
If they want to come out with some historic themes or "civilizations", sure, I'd be interested. I'm still interested in the modern game, most of the time.