Actually, Dave Mustaine has used at least 3 rhythm tracks on every Megadeth record. He does 1 Left and 1 Right, and has the second guitarist do 1 right up the middle to fill it out. This goes all the way back to at least "Peace Sells..." and Megadeth were not the only band to use more than 2 rhythm tracks. Hell, I read somewhere a long time ago that "...And Justice For All" had 3-per-side for the whole record, plus the extras. Doing 3 or more total rhythms in metal is not a "new" practice guys. Sorry.
What people aren't getting is where to use it, and where to keep it simple. I have the tighter guitarist track at least 2 rhythm-per-side for the whole song, but I don't use all of it. The advantages are that I can get very picky about which 2 tracks I'm using at any given time, and that the bigger/heavier riffs get bigger/heavier with those extra tracks.
Bottom line: Do what you want, and worry about getting good at doing it YOUR way. But don't try to justify your methods to others by making vague references and shitting on tried/true recording practices.