We have experience with voice controls and that solution is very situational. Like you said a game will have to be a slow paced game, almost like a point and click adventure games. We know that voice control is not used for main buttons or actions in games, for example moving character or attacking due to delay in voice recognition and timing your words. Basically it's a terrible solution for precise input. However voice control works very well for actions that are trivial. For example opening inventory, navigating menu, interaction action etc. I think a game like point and click adventure style could work but you know, instead of pointing and clicking you use voice and words.
Pressing multiple buttons for unique action sounds cool! Maybe a temporary bonus or something. I am not sure about button mashing. Button mashing should be avoided in my opinion.