After running around like an idiot for a couple hours wondering why I kept fixing, then breaking my mapleader in Vim, I finally figured out it was because I was trying to switch the semicolon and colon so they reversed function. Which actually was not breaking my mapleader so much as rendering the commands it tried to print useless, as commands written like
:nohlsearch were actually printing as
;nohlsearch and of course Vim had no idea what to make of that.
So instead I’ve now mapped
<leader>; to the semicolon for the repeating character find, and it seems to be working alright now, and I’ve got Command-T working also. Though I’ve half a mind to attempt to recompile terminal Vim with Ruby, because it’s kind of irritating to have to use MacVim for that sole purpose.