I recognize that I run a strong risk of AFSBAD ("asking for something BBedit already does"), but I would love to be able to put a different file into a split window: file #1 in one split and file #2 in the other.
Tiling windows is fine, but it puts two sidebars on screen, taking up too much space, especially on a laptop. Of course, I can close the sidebars, but having a different file in each split of a window not only saves a few keystrokes, it also feels very natural, conforming to the workflow of those of us who frequently work on two related files at once.
An option to hide the sidebars when tiling would help, although then I'd also want the sidebars auto-restored after the tiling ends.
In short, I am a bottomless pit of wants.
-- David W.