Well, that would certainly complicate matters. But this post is assuming that Kanter has negative trade value, which I'm not sure is the case with the new monster cap. When you have stiffs like austin rivers making $12M then Kanter's $17M doesn't look so bad. OKC might be better off pawning him off on some desperate small market team that will give up a real asset. A contender might need him too, enough to dump a prospect and late pick perhaps.
And by not including Kanter in a Westbrook trade with us means they can focus on getting more assets for a proper rebuild, as Ainge would use Kanter's big contract as leverage to give up less. We're not the right buyer for him.
Kanter and Westbrook's salary combined would total almost $35M - we'd have to dump amir, JJ, bradley/IT/crowder + loose change to make it work.
we'd lose a lot of players, and, assuming we resign westbrook at $30M+, we'd have $77M tied up in horford, westbrook, and Kanter. that wouldn't leave us much space for the rest of the roster, even with the cap jumping to $102M the next year (NOT the original $107M that had been projected earlier by the media).
Doesn't look like a championship core to me, especially if we gut our young prospects/picks in the trade.
I think I'd rather keep the cap space and make a second big trade/FA signing.