As a tight rock mix makes it hard to distinguish reverberation details, I am convinced that the more “dry” is the vocal, the better it will fit in the guitar “wall of sound”. Of course, unless the music mixing service client is looking for an “arena” type sound I mentioned. Otherwise, a very short room reverb will be more appropriate, or a slap back delay as an alternative. I think that reverberation makes the sound too “right” and “polished”, which isn’t very good for rock songs mixing. However… There are situations when a song or some part of it simply demands an explicit reverberation. In that case, I do exactly the opposite of what was said above – I make a faaaat chamber or plate reverberation to highlight an epochal moment.
There is one stereotype among the mixing engineers, for which I have no stomach. It has literally become a standard to apply distortion to the vocal channel when mixing rock music at the earliest opportunity. The usual explanation is “well, it’s a rock song – that’s the way it’s done here!” Yes, distortion of the vocals, of course, makes them more edgy, but when it becomes a mere tribute to the tradition, rather than a well-judged action, this approach turns mixing vocals into a mockery. I don’t have anything against this sort of extra flavor processing, on the contrary, I often use it in my work, but only when it forms a natural addition to the overall mood of the song and highlights music emotionality. I’m sure that’s what your service’s clients expect. If an artificial overload of the vocals makes them sound smoother alongside with the guitar sound, then everything you’ve done was correct and appropriate as a mixing creative solution.