THIS.I too don't really see the any reason not to love the Horford signing.
He instantly becomes the Celtics best player.
He fills a position of need.
He makes the Celtics one of the top few teams in the East (behind Cleveland, but arguably as good a team as any other team)
The money with the new cap and the cap going forward will end up being reasonable (and is a free agent bargain compared to the money being thrown at free agents this past week) in the new economics of the NBA.
If they didn't sign him, I am not sure where they could have used the money and an impact free agent shut out was possible.
Adding on one of significance, and saving the money does not necessarily lead to a bonanza in 2017 free agent market (1 in hand is worth 2 in the bush)
and the Celtics now have perhaps a 25% to land KD vs. a <1%. (I know you can argue the numbers, but the fact remains that the Celtics now have a much better chance to land KG)
I guess to me I would much rather have Horford + max contract room now, than 2 max contract room next year.
If the Celtics land KG, Ainge deserves GM of the decade.
If the C's don't sign Horford, they probably use the same salary slots for mediocrity like Jared Sullinger+Courtney Lee/Jared Dudley or Evan Turner+Cole Aldrich or Myers Leonard+Aaron Aafalo.
This deal sets the team up nicely to get production from 4 quality NBA starters locked in on market/below market deals (IT/Bradley/Crowder/Horford) and then fill out the roster mainly with guys on rookie deals that are still developing (Smart/Jaylen Brown/KO/Rozier/Mickey). If they miss on Durant, then they'll also bring back Amir+JJ on reasonable one year deals that leave them flexibility to go hard after Cousins in-season or another max free agent next summer.