We've discussed this before, but I also believe PHI should move on from Embiid and acquire a top-tier scoring guard who can create for himself and play off-ball. Of course, Kemba would be great, but that isn't going to happen - so Beal and Lillard would seem like the top targets.
If Philly is stuck with Horford and Harris, it really isn't all doom and gloom. They should be playing C and PF, respectively anyway. And with Simmons' height, they would still have plenty of size. A legit #1 scoring threat would really help that team run a lot smoother and they would get a lot more easy buckets on the fast break and even in the half court without Embiid down low. I would think there would be quite a bit more ball movement, too, making everybody happier.