I think creating the whole leveling sequence is complicated and unnecessary, also adds complication of overriding it. it's too much interface to see happen before other things that probably will be prioritized.
Even Better and Simpler Option
I think just being able to CTRL-[QWER] to set what I want next ahead of time is good enough. So when I next level up, immediately auto up the skill, whichever of QWER has been selected. Easy for visual interface, you can just highlight the "next" one. If there is no "next one" it works as it does now, requiring a keypress or click.
We only really need to decide what happens on the next level up, and generally there is a good amount of time between levels, that gives plenty of opportunity to hit the hotkey, set what I want next (and easily change it by hitting another hotkey if you change your mind).
If you wanted to toggle off the what I want next, hit the same CTRL-combo, so if I wanted Q next, I hit CTRL-Q, if i want to just change back to deciding in the moment, hit CTRL-Q again. If instead I wanted E, hit CTRL-E.
Simple.