You're not winning the title with
Horford
Butler
Hayward
Thomas
and company
in the next couple of seasons, so why make such a move (Butler trade), if it costs you high end picks?
Center needed (big from 2018 draft)
Horford
Hayward/Brown/Crowder
Bradley
Thomas
Fultz or Fox
Smart
Rozier
Stashed foreign dude(s), possibly
Other bench guys to round out the roster
gives Boston an excellent chance to remain near the top of the East in 2017-2018, and then they grab their center in next year's draft. That gives them a, mostly, young and improving team as Bron Bron starts to age. That seems smarter, to me, than pissing away picks for Butler, who you're hoping is what Brown basically becomes.
Bottom line: I get Fultz, I get trading down and taking Fox, I get trading down and taking Ball, I don't get Jackson unless they think they missed on Brown, and I don't get trading picks for Butler.