If we can trade IT for Butler or George and add Fultz, I am not sure that makes us worse, just not really any better. We still lose in the conference finals at best. I don't see that type of trade happening in any case anyway. I could see us trading IT for a high ceiling young player (Myles Turner was a good example) but I can't see a team wanting to trade a high ceiling young player for IT. I realize that if we don't trade IT, we risk losing him as a FA for nothing but I don't see a realistic alternative.
I am not that worried that trading IT would cause the team to regress in the near term if it is a step towards a better team in the medium term. I just don't see how a trade matches up.