Random Unit Variation...Good or Bad Idea?

I'm aware that numbers and stats are a big part of executing effective AoE strategies and that immersion and realism are not what AoE is about, but sometimes I think it would be neat to have a little variation built in to unit stats. For example, if you create a bunch of archers, instead of all of them having the exact same HP, attack, reload time, speed, etc., maybe their HP varies by a few points or some are slightly faster or slower or maybe have a little extra range or faster reload time or something. I know that with some stats an change of just 1 can make a big difference so some things should probably be left constant, but I thought that perhaps it could add some random spice to the game or create new strategies. The differences should even out in larger battles, but smaller skirmishes could get interesting. But I don't think I know enough to say whether it'd be neato, totally alter or break the game or have no real effect at all. I know at least it would make SOTL's job a lot harder. Thoughts?