I see what you mean, Chris. I've just put a reel on a rod butt to see (more wet weekend stuff) and I notice my thumb is lower down and slightly around the rim, making the pressure a bit more of a squeeze in together with a push down. I stopped short of harnessing the cat to simulate a 10lb fish. It's what I've got used to doing, and, for things like barbel and carp, does seem to give me a better purchase to apply strong pressure or even lock the reel.
I can't claim any credit for being flexible about winding one way or the other. It's just the way it is.
I mentioned elsewhere how much I'm enjoying the cp with a proper drag I've been using through the season. You can "freespool" it and thumb it as you wish, but for barbel and carp around snags, the drag can be set, increased or decreased as you play the fish, and thumb pressure added as you go along. It's rare I'm trotting any distance with cp's, something I'm thinking you do a lot, so my comments come more from that kind of use. With the drag strong on, you can take your hand off the reel and add it the butt above the handle if need, and no more risk of burning your thumb or smashing your knuckles on the handle.