Eh, not so much. But yes, if you hear reverb it is too much. The overall sound should seem better, but with no audible reason why it is better. But if you can hear the reverb, it is too much.
Reverb is also a way of "backgrounding" an instrument. The more reverb, the further away the sound seems. (Again, the brain reconstructs the "room" sense from what it hears.) So any given instrument might need more or less reverb, depending on where you want it placed in the mix. Panning also helps - pan the flute 30% right, pan the lead guitar 43% left - to give the sound a bit of structure. Of course you probably wouldn't use panning in a live performance. Maybe, but not likely.
This is why professional recordings are made in a sound booth. No reverb at all. Then you go in and apply the amount of reverb you want to each channel post-performance.
For recording a live performance they usually have a direct mic on each instrument/vocal, and then one or more mics recording the ambient sound in the room. The room mics provide the reverb, and they can add or take out reverb as needed, while the direct mics provide the "dry" direct, non-reverb sound. Then the editor mixes to taste.