So I have in mind a separate "Layer Settings" (or something so) tool to control ALL that extra layer settings I think we use often and, specially, that "trial and error" ones like masking and layer blending, to have the ability to play with it just in the way we play with particles using that "Particle Tool", although I'd like to have as most settings as possible at first sight and use pop up windows only if absolutely necessary. Definitetly, although much of this real time changes wouldn't be visible in the viewer, it could be very handy and save lot of time and clicks before "Ctrl+Ring".
Well, I'm treating to remember the very few LUA skills I think I had in the past, and this kind of "easy" exercises (actually I understand for "easy" anything don't involving matrices


BTW: Actually, is still quite easy & quick to animate layer visibility clicking directly over the "Layer Visibility" animation channel along the timeline, so I'm not sure if it'll worth the space to include another shortcut for it...