I think it's less about "too many effects" on postprocessing, and more about layering the right effects in postprocessing. I'm still learning all of this too. Heh.
But there's an order to things like compression, EQ, condenser effect, that sort of thing.
It's like the more you do to make a sound interesting, the more you risk making it murky and muddy. It's like the spectrum is between murky (overprocessed) and flat (underprocessed), but then the art is to make it neither murky nor flat, sort of like you're wall jumping up a wall between murky and flat, where the higher up you get, the less murky and flat it gets, but you always have to trade between the two until your mix is perfect.
That's the sense I have for now, anyways, we'll see how I feel about that in a couple more years of doing this heh