When I got my TT, I had few ideas as to what I wanted outside of "bathroom, kitchen, place to sleep, place to eat, place to relax". I lucked out and got a TT that worked pretty well for that, so I didn't feel the need to have to make changes.
When I decided to get a C, I looked at various floorplans and found one I rather liked, but then I saw the clipper and it has been perfect. I LOVE the layout. There isn't anything I would change to it. I love having the kitchen at the back with a big window - it makes it easy to hand out food, etc. to another person who can set the picnic table, etc. I love that the bathroom is in the corner so it doesn't block the light from the windows. I love the two big windows on either side with the dinette and flip-over couch under them. The cabover bunk is a cozy little nest at night (and stays warmer at night). The cupboards are all in the right places so that things are organized according to area (kitchen supplies are all in the kitchen, etc.).
I do think it helped that I have spent 30 years in small houses that aren't conducive to rearranging. I think it makes it easier for me to quickly identify a "negative" configuration.