their offense (and defense) revolves around Horfords unique skills

It only looked like that because Kyrie and Gordon were injured. The team was Horford + guys with minimal big game experience.

They have to figure out what they're doing with Smart this summer. If he gets an offer sheet to the tune of $12 million it will be difficult to match for the Celtics given their current cap situation and future projection of their salaries.

I think they'll move Rozier and Morris if Smart is re-signed. Moving Horford for Melo gives them the opportunity to go after another major free agent when Kyrie opts out for max money and Melo's contract expires.