When you compare Sabonis and Brown, it is hard to compare their defense. The better question when considering Sabonis is to compare him to say Horford. That is who Sabonis would replace, or RWill (very different style player). If we traded Brown for Sabonis and whatever, Brown would be replaced by some other guard.
Sabonis would be a nice big to add. No, he doesn't hit the 3 and he can't alley oop dunk like RWill, but he puts up 20 pts and 12 rebs pretty consistently. He is also a very good passer, ball mover. He is an all star level big, nothing to sneeze at.
In many ways, a skilled big suits our team better than a scoring wing. We have Tatum, perhaps the best scoring wing in the game. But the overall value we get still would have to match the high value that we have in Brown. To me, Sabonis on his own does not have quite enough value.
I don't think we are trading Brown. Maybe if we could get Towns. I can't think of too many others. And I don't think we would trade Brown for a hodgepodge of lesser players and picks.