After the initial shock of the trade, this is actually pretty good. I think most of us were hoping to get a first in a trade. Obviously, that wasn't gonna happen in the off season as we could all see that high salary players had no value at this point in time. To make it happen, we would have needed to hold on to him until the trade deadline. That could have brought bad blood and is generally not great to go against the wishes of a player for a long time. Especially since his wishes are family oriented. People getting on him are dumb. His reasons are valid.
By trading him, Hughes showed class and a willingness to work with the players. A positive reputation can help eventually when trying to sign players.
On top of that, Matheson is actually a good player. As others have said, younger and cheaper. He is from here, which is nice. If he fits, he can be here for a long time.
So if we analyze value of Matheson and Petry, it is close enough. Matheson doesn't want us to trade him, so that is a more comfortable situation.
Poehling for a 4th isn't great, but the reality of it is Pittsburgh probably wanted a sweetener to make the deal. Oh well. He was expandable, even though I think he still has some potential.
The Petry trade was never gonna be a hugely important trade for the rebuild. I'm satisfied coming out of it with a good piece that can help for a while and either fit the core or be traded for what will most likely be a decent return later.