I could not disagree with this idea more.
This is exactly the problem, the rank 5 lock has INCREASED smurfing by tenfold.
I suggest removing the rank lock altogether and then the peeps who get "stuck" at rank 5 would no longer be the victims of high rank smurfs hanging at rank 4-5, getting beat around for 40 matches in a row. those losses would result in naturally going down ranks where they could actually compete again.
And peeps who don't like certain formats ( I hate 3vs3 and won't arena for the week if I get stuck there ) will not be stuck in that format.