I'll throw my 2 cents in. Do you mean bi-wire or bi-amp because there is a difference. Bi-wiring is from the same amp with two sets of outputs and cables where bi-amping is two separate amps.
I used bi-wiring on my Sequel II's and there was a difference. My amp has two sets of outputs. It was a bit more "refined" in the sound and a bit more seemless between the woofer and the panel. It seemed that the low mids from the panel were better defined and that the upper mid/bass from the woofer seemed better. I guess a bit cleaner, effortless, throughout the frequency range too, would be more acurate.
Using two amps will present two different signals (levels) to your Ascent i's. Neither amp will really work that hard because they are dedicated to a smaller frequency and impediance swing, there by, disapating less heat and working less. There are some here that use a solid state amp for the woofer and tubes for the panels. (cool!) The only caveat is that you have to be able to balance the volume between the two different amps. There are attenuators (kits?) out there that can accomplish this at a reasonable cost.
I would try bi-wiring first since it is cheaper, if you amp can do that. I am not familiar with the Pass but others are here and can advise better. See if you can borrow an amp and it does not have to be a powerhouse to drive the panels for about a week or whatever to see if you hear a difference.
The real key here is if you can hear difference and is it worth the money. Of course there is always the WAF to deal with too