This notion that Jimmy Butler is only marginally better than Bradley is ludicrous. Jimmy Butler is a top 15 player in this league. He has legit SG/SF size, plays good defense, and can create his own shot. I love Bradley but Butler is a superior player.
As far as cost goes, you are going to have the give up assets to get a top 15 player signed on a very team friendly. Only untraceable players in my eyes are IT and Horford and maybe Smart. Everyone else and picks are fair game.
This idea that Butler is a surefire top 15 player is getting old now. He's not on the level of guys like Durant and Lebron, the only type of player that would change our outlook this year, he's on he same level as guys like Wall and Lillard. Trading for him is the epitome of trading to be second best.
A year ago most of this board was against trading Crowder, Bradley and the Nets 16 pick for him. Crowder and Bradley have improved, Brown looks legit in his first year, a mini Butler in fact but with a higher ceiling. I see no reason why we should waste assets now to tie ourselves to mediocrity. Ainge has done a great job being patient so far, I hope he holds the line until a real difference maker comes along.
I hate to break this to you but there is like 3 real super stars in this league and they aren't likely to switch teams. That doesn't mean the C's should attempt to add a top 15 type player because they can't get one of those 3 guys. IT, Butler, Horford is a good core and it still gives the C's flexibility to add to it.
You're right, those guys aren't switching teams. Unfortunately, two of them are on one team with 2 other all stars which makes competing for a title this year extremely difficult. Not impossible, just very difficult. The thing is, the alternative is to have 2 more chances at drafting elite players, whilst still having a very competitive team this year and the chance to add to it this summer.
Let's set aside whether I think Butler is worth a certain price or not because that is completely subjective. If no deal is made by the trade deadline, where does his price go? If it currently sits at Bradley, Smart and Nets 17 for example, can it go up further? Or is it likely to come down? He's on a team that will probably have a mid 20s pick this year, whose best young player is probably a back up point guard in this league, two ageing veterans who probably don't stick around after this year unless they smell money. So they become a lottery team with nothing to show for it. At that point a recently drafted Fultz/Ball/Smith Jr to build around looks pretty attractive. You would want some other assets along with it, but there's no way you're asking for Bradley, Smart or Brown anymore.
From our perspective, we would have the chance to sign a max FA this summer, something that DA seems intent on. Even if we falter in that attempt and a Butler trade can still be made, we could use our cap space to extend IT and then make a trade for Butler. That would help our cap situation heading into 2018 and may even mean we can keep Smart and Bradley as well, at least in the short term whilst we balance our roster.
Back to my subjectivity, I don't consider Butler a top 15 player in the league. I have in no particular order; Lebron, Durant, Davis, Curry, Thompson, Cousins, George, KAT, Lowry, Harden, Westbrook, IT, Leonard, Griffin, Paul, Giannis all before him. I then have Butler in a tier with Wall, Lillard, DeRozan just ahead of guys like Porzingis