This is a great conversation about organizing the structure of lines. Yes, voice actors may just want a simple list, but a heirarchical organization of lines that allows for more detail to be added sounds like a good idea. It needs to be clear what is the bare minimum, but these added details sound awesome to me. Perhaps an ideal solution is to have the "simple list" that covers everything needed and then a "detailed spreadsheet" that helps the overachievers add character, situation, or other contextual variation.
Firstly though: I can't find any docs for how voice actors, musicians, etc can contribute. Shouldn't there be a section on 0ad.com/participate or at least a page in the wiki? As someone who was bothered by the lack of variation in voices and am still trying to figure out how I can help fix it: maybe this is a big part of why the pool of voice actors is small.