I don't know. Permanently is a very long time. I'm alright with trying it out for a while and seeing how it goes. They certainly started out better than they have in quite some time. I think Smart's offense, or lack of, works better with Irving, Tatum, Horford and Morris.
I very interested in seeing what a bench with Haywood, Brown, Terry, and Baynes looks like.
Personally I think Brown could really shine there, as I think his role would be more defined. Might be wrong but thought he's been playing much better last 2-3 games. Could be perfect. As far as accepting a bench role. If Haywood can, I think Brown should be cool with it.