Not nuts. If you're focusing on legacies, you only ever need shutter priority and you're set. Tri-navi dials aren't much use if you're using the lens, and the 24 megapixels makes high ISO and wide angle life harder. Plus you get a smaller body. I would however, recommend with the money saved, that you try out the 5N EVF. It is special, and trumps the fixed EVF in my opinion
I've never thought about replacing the 7 but the scorching deals on closeout 5Ns do get my attention. I've got my eye on the Voigtlander 15mm and from my readings I gather that while the 7 can work OK with it, the 5N has significantly less color cast issues. So I could see a 5N or 5R eventually for 2nd/backup/wide-angle/touchscreen use.