Philly should have an elite defense if not the #1 defense in the league.
Losing JJ and Jimmy offensively is tough, but defensively, huge upgrade to get Horford and Josh Richardson. And Matisse and Zhaire project really well defensively too. I like what adding Al does for keeping Embiid healthy too--getting him rest and having a good backup C was the missing link last year.
Backup PG is an interesting one to watch too. Raul Neto is pretty boring but effective. Average at just about everything. Trey Burke gets buckets (though he's bad defensively).
But more than anything, the East is just kinda garbage. Indiana and Miami will play you tough every night but they do not scare me. Milwaukee got worse. Boston could take a step forward this year, but huge unknown. I like how Brooklyn has built their team a lot but until Durant is back, they're not contenders.
I know nothing about the West by comparison, but I agree with le bone about the Jazz. Great roster.