There's probably about 5 threads about Butler at this point. We've seen it referenced in dozens of articles that Butler is the key to acquiring KD. I don't agree with the premise. I think (assuming he actually leaves OKC) you can convince Durant without having Butler in the fold.
Also, some of the trade ideas I see would actually make it impossible to use double-max cap space. For instance, one of the most popular ideas I see is centered on the pick ending up top 2 and simply shipping out Amir + Jerebko and the pick for Butler. If you did this, you'd still have 25 mil for signing Durant, but no longer have max room for acquiring a second star. That then becomes counter-intuitive. You're adding a star sidekick in Butler, but removing the possibility to add a star sidekick via free agency - all while losing a pick that could develop into a star in it's own right.
I read Ryan Bernardoni's (dangercart on Reddit) article in which he lays out a dream offseason acquiring Butler and still maintaining double-max cap room:
http://www.celticshub.com/2016/05/02/navigating-the-offseason/One of the biggest points he makes is that Boston would be taking a bit of a risk since any Butler trade is most likely to happen on draft night and draft night is weeks before we can officially talk to Durant. His hypothetical trade offer was the Brooklyn 1st, Avery Bradley, Marcus Smart, RJ Hunter, and James Young for Jimmy Butler.
Quote from Ryan Bernardoni's article:
The bigger risk, and a definite possibility given the timing of the offseason, is trading away the Nets pick for that Butler or Cousins level player but then not having the other shoe drop. If you, for example, make the Butler trade for the Nets pick, Bradley, and Smart and then, failing to entice Durant, bring back Sullinger and add some other mid-tier veteran you’re pushing up your age and cost profile but not getting to the realm of title contenders.
He makes a good point here and it's one of the several reasons I'd prefer to just hang onto the picks/prospects and approach Durant in free agency with the team as-is. I think the team is plenty appealing already and you can spell out all the potential follow-up moves to Durant directly. I wrote a lengthy article about my rationalization for CLNS Radio here:
http://clnsradio.com/boston-celtics-news/item/13678-boston-celtics-why-not-build-a-big-5In it, I imagine a dream scenario in which Boston ends up with a team like: Thomas, Ben Simmons (if the pick lands #1), Durant, Max Free Agent (Horford? Derozan?) + another impact star (Marc Gasol? Melo?). You could theoretically build a "Big 5" and depending on the price of that final impact star, you might be able to keep Smart and Crowder in the process.