Real +/- rankings per ESPN as of 1/24/2017:
Crowder 8th of 80 SFs
vs
Covington 22nd of 80 SFs
Noel 42nd of 93 PFs
Saric 93rd of 93 PFs
Do I trade the best player in the deal for Covington, a rotation player, Saric, whose defensive shortcoming are substantial if his Real +/- is to be believed, and a rental in Noel?
No. Not interested in Covington or HOFer Saric, and if I wanted Noel, I'd put a bid in for him that I can live with next summer. Sixers would be nuts to match highest bid and I doubt Danny would even bid.
BTW, Smart's Real +/- is 18th among PGs vs 93rd (i.e., dead last among PFs) for Saric. Both are 22 yo. Doubt any GM would trade Smart for Saric straight up.
http://www.espn.com/nba/statistics/rpm/_/sort/RPM