The trade makes sense for all teams. MIL getting Lillard is of course brilliant. He is a top player to pair with Giannis. And not really giving up all that much. Holiday is good but replaced by Lillard. The core remains in tact. It looks like the primary backcourt will be Lillard and Beasley, that is exploitable from a defensive standpoint but Lillard and just about anyone is still a dangerous backcourt.
I like POR getting Ayton. I don't understand why PHX has given up on him. He is a great player to add to the young mix in POR. PHX kind of splits Ayton into Jusuf Nurkic, Grayson Allen, and young bench players. That isn't great in my mind but it seems that they had made up their mind to move on from Ayton and they need depth so I guess we'll see.
Overall:
POR: A- (they did well under the circumstances, but are still giving up the best player)
MIL: A- (hard to give an A+ when they give up Holiday)
PHX: B- (They got some depth but I don't think full value for Ayton)