There's a lot to question here. On paper, they look better, but both teams have major question marks now.
Philly
The biggest thing is whether Harden and Embiid will play well together, and how committed Harden is to winning and how much he has lost in his game.
I think they'll work fine enough together, though I'm not sure whether they'll work well enough together to win it all, especially this year with a third of the season to coalesce. I also think they're going to miss Curry more than is being let on. And losing Drummond hurts some, too.
Brooklyn
This one is super interesting, as this is really a crapshoot I think given all of the contextual factors. Theoretically, Simmons should complement that team well and provide them some much needed defensive presence. Curry is just another ice cold shooter for them, too.
But that is HUGELY risky to have probably three of the biggest headcases (less so for Durant but he's getting there) working together in the same locker room. That seems doomed to fail, especially with a coach like Nash that is mainly a rubber stamp for the stars. Also, given Kyrie's vaccine concerns, Simmons' ability to play, Harris' injury, and KD's injury which seems to still have another month or so to go, I don't think they're winning anything this year. Dug themselves too big of a hole this year.
Buy, yeah, I think long-term the Simmons addition is probably going to blow up in their face. I think he's a shell of himself when he comes back due to all that has gone on and his much lesser presence in Brooklyn, and I think while they're still a highly elite shooting team, they took a significant step down in the scoring department with the downgrade from Harden to Simmons. And that was their major key over other teams - always being able to have two elite scorers on the floor at all times.