I think we should try to get someone like Monroe and make a run with IT, Horford, and Monroe (or whoever). No need to trade IT. i am not totally against it if it is a surprising good trade but I don't see it as very likely.
We aren't going to win a title with that team (assuming we add a Monroe type big) but we should win a round or two in the playoffs. That is good business for the Celtics. That could be our core team for 2016/17 and 2017/18. It can be an entertaining run. Along the way, if we get a shot at Paul George or some other big name, maybe we go all in.
At the end of 2018, assuming we haven't done an all in trade, we could still have Smart, Brown, Rozier, BKN-2017, Yabusele, Zizic, BKN-2018, and a few others. We could trade Horford at that point for young players and start a reload. That is not a bad position from which to start to rebuild. Depending on how some picks work out, we could be a fringe playoff team.