I have my standard Arena team in and am just going to keep playing to find where my new balance point is. Not changing my team will find me matches, eventually, that are the same strength. I may look overpowered to some players but I am getting to point of win one loose one. I will keep dropping Trophy level until I find it.
Boosts shook up match making and trophy level pretty dramatically. It is not going to sort itself out overnight. I think of it like putting 6 months of playing the game into a one week period. BAM, several levels overnight instead of slowly leveling up teams. Players are going to have to find a new trophy level to equalize at. Many will not be happy they used to be at 4500 Trophies and now they are at 4000. It is their new trophy range for their skill/team level. It is going to take time (or boosts) to get back to where they were before.
So yeah, Arena dropping is now legitimate, intentional or not it is going to happen to many of us. Unless you were one who got the advantage of leveling dramatically overnight, you are going to legitimately drop Arenas.
Those who are intentionally dropping to avoid the initial slaughter, fine. Things will sort themselves out. They will eventually want to rise back up and find their new high trophy level. Those that drop just to pound on lower teams and get incubators, that is nothing new.