My wife and I have had this debate forever. Our kids are now 21 and 24, and we figured they would move out and not camp with us any more. No such luck. :)
So two years ago we actually upsized to a 28' TT and we apparently made the right decision (although my wife still stresses when I'm backing the TT into a site or at home).
For the first time ever, we parked the TT at a CG for the month of August. So far we have gotten a lot of use out of it, both my wife and I, as well as my two daughters, and some other relatives as well.
The TT has the oversized bunks which work well with older kids, and sometimes us or other adults. And for us, the queen size bed is a must.
The 28' TT works well for us, because due to my medical situation and work schedule, we cannot take extended long distance trips, so this size is manageable. But I can see the benefit of downsizing if it is just going to be 2 people and you take frequent trips.
BTW - that Minnie is gorgeous!