this is an interesting idea. However you are only looking at 1 nutrient. Perhaps it would be worthwhile to find a yeast nutrient with low or no N but I have noticed (in a very unscientific way) better results when using nutrients then when not, at least with big beers.
Servomyces and GoFerm (I think) have relatively low nitrogen levels, but I think they still have some. I can't find specifically what they contain, but the descriptions of how they're made sound very similar. I'm completely on-board for having proper yeast nutrition, don't get me wrong. My gut is telling me that yeast nutrients that also contain additional nitrogen and ammonium salts like Fermaid-K wouldn't really be appropriate for wort fermentations, and something like Servo or GoFerm would be better.
In the kind of beer fermentation you'd need additional nutrients (big beers), you probably wouldn't be able to detect vitamin/mineral faults anyway, as long as you didn't add way too much. Without a lot of lab testing, you're just guessing if your wort needs extra nutrients or not. I "just guess" on a lot of brewing-related issues, like yeast counts and AA% for my hops, so I don't know why this makes me uneasy.
As an aside, I've read that winemakers that don't like to deal with formol titration to determine nitrogen levels just use their nose, and add nutrients if the yeast starts throwing sulfur.