If you're a GM worth your salt, I don't think you should be afraid of dealing with any other GM. You should just turn down the offer if you think it's a bad one.
Regarding making the Cavs stronger, I don't think we should really be too concerned about that. I think DA needs to focus on making the C's better and not get too concerned whether or not other teams upgrade. For example, if we can trade Bradley+Lee for Love but it means Cleveland lands Melo, we should participate in that trade because that is tremendous value for Bradley+Lee.