Well, because of one of the stupidest rules I've ever heard of (Rose rule), we would have to wait until Kyrie re-signs next year to make a deal with NOP for Davis anyway...unless of course we trade Kyrie, but I don't want to go there right now.
Losing Cousins really shouldn't hurt NOP very much since they were better without him this season, but Rondo has proven to have an impact on winning. Payton seems like a perfect replacement for him, though.