Implemented in commit 8c59c75. If a V12.7.4 update happens, I'll see how feasible this is to backport (I think it should be relatively easy to do); otherwise you'll get this feature in V12.8.0.
Workaround for now: If you want to change to Traditional layout, just delete the "hotkeys.ini" file in Settings. If you wanted one of the other layouts, rename your Settings folder to something else, then run NL and choose the desired setup when prompted (NL will think this is the "first run"). Then, exit NL and copy all files from the old settings folder except hotkeys.ini, into the new one.
Alternatively, if you want minimal layout, you could simply blank out (but not delete) "hotkeys.ini", which would give you a completely empty hotkey setup. Then, manually configure the 5 assignments the minimal layout has (if you even want those) - scroll wheel up = zoom in, scroll wheel down = zoom out, MMB = pause, RMB = click-to-scroll, Esc = quit.