There was a visible problem when Harden was at Nets. There was more than one player who got a leader character. And this was causing some conflicts in the team. Now he can play freely and lead his new team. And I'm expecting him to make a good duo with Embiid there. Harden would play as a point guard and Embiid would score like always. This would bring an extra power to Sixers. They are already doing very nice in the regular season and they can perform better than this in the playoffs like this.
I think I read one report stating that Harden had wanted a role similar to what he was in Houston.
This was simply not possible. In Houston he was a one man show that could do whatever he wanted whenever he wanted. The Nets had a Big 3 which will obviously not work out with an individualistic approach like this.
The Nets will be remembered as one of the biggest whatifs in NBA history.