Personally, I find tooltips far more distracting that just a tiny bit of color on the screen.
under your scheme, if the patch is even remotely alive, much of it is going to turn red right after opening
what about displaying the init value in black, and the current value in red or green, depending on whether its rising or falling
eg _=___=___ | osc~ 440| | 557| | (hz)| -=---------
or something (i even forget if osc~ has one outlet its been so long since i touched pd) clicking on 440 would reset it (so you dont need to cluter the patch with an extra [440(
cc