robin,
Speaking personally, flying something like a Cub after the usual suspects is not just about learning new techiques - it is a whole new way of flying and everything that goes with it.
My perspective is that it is different, but not that different. I'll refrain from saying additional fun I can't say that t/d is more fun than flying anything else, just different. For me the incredibly basic and austere nature of the t/d that I fly encouraged confidence in shedding all the pointless gadgets and knickknacks. One even learns that sans radio is a total non event, good job because for an aircraft without the ability to charge on the ground it can be a frequent event.
If you want to have the opportunity to completely turn everything you thought about flying on its head, try a Pitts; that really is an eye opener in more ways than one!!