I built a dedicated 2-channel system. I have spent years here at Audioholics listening to people say bi-amping is a waste of time. My DEFINITE answer is, it depends.
My experience based on MY equipment.
I started with (1) Denon POA-2200 amp, and (2) MB Quart QL-S830(4ohm/87db.) The sound was impressive, but the treble would flatten-out when pushed. Pushed a little harder, the mids(6.5" woofers) would slap. At first, I thought it was overpowering the speakers. The Denon POA-2200 is a pretty sweet amp.
I added another Denon POA-2200. Had Bluejeanscable custom make vertical bi-amp cables for each amp. Each amp has gain controls for each channel. With this, I am able to control the gain separate for the tweets/mids. This is an invaluable feature. The treble NEVER flattens-out. It remains extremely detailed. The mids NEVER slap, and it's truly amazing how much output I get from these two sets of speakers.
System is playing full-range, with no sub.