Although likely to be a mistake by the OP, turn based RTS is quite an interesting idea. Perhaps it can be real-time ala RTS when both players are online together playing simultaneously, which then switches to TBS mode when one person goes offline. Of course it wouldn't be very good if the TBS portion of the game was completely different from the RTS, otherwise its just two different games, but if one were to design the gameplay in such a way that the differences are subtle, and if the core game was TBS but you'd get additional real-time features if both were online at the same time, you might get an interesting mechanic there. Something to think about when developing my next game definitely.
Nothing defines them, because they're different, like WRPGs. Again, I would suggest looking at some more JRPGs if you think every one of them is turn based. The 'Tales of...' series would be a good start. Also, the Total War series is the most awesomest turn-based RTS ever. Just sayin'.
even better is a mmotbrts. (don't suppose any of them around is there?) Actually just the mmotbs will do.
