BP based matchmaking would mean people with good ninja combos would have free wins over others of otherwise similar BP, which is a problem in itself.
Changing the 1 minute match anyone would probably be a better solution. Instead of anyone after 1 minute, maybe gradually increase the range based on how much time has passed by. For example, up to 2k pow difference for < 1 min. up to 4k difference at 2 mins, 6k at 3 mins ect. The matchmaking time would be longer, but it would get you less frustrating (mis)matches. There would still need to be a match anyone limit, say at 5 mins, so people with absurd pow would still be able to get matches.