I like James Harden to stay with the Sixers. He is quite going along well with the team, especially with Joel Embiid. Their duo is even much more effective than the famous Embiid-Simmons duo which turned out to be the worst after several seasons.
Since you have mentioned also that he has the player option for the second year, then it's possible that if the Sixers turned out to be bad next season, James Harden will leave the team and find another one that will suit his needs.
Harden went to Philadelphia because of his personal ties with people in the city. He wants to spend his time there. That's why he took less money to be on the team. He wants to bring a championship to Philly and be the man on the party scene there. For that reason, I don't see him leaving for basketball related reasons. I think his deal was a good one for everyone and I hope that it turns out better than his time in Brooklyn with the Nets experiment.