While the appointment of Mohammed Mustafa will likely be well-received among Western diplomats, it's not clear if the PA has enacted enough reform to satisfy the US. There's optimism that a well-educated technocrat like Mustafa can help push the PA in the right direction, but this has yet to be seen. Either way, Mustafa will have a lot on his plate.
Mustafa, who is an internationally respected economist, has been appointed to clean up Fatah's endemic corruption. He is also tasked with unifying the PA's control over the West Bank and Gaza — something that Prime Minister Benjamin Netanyahu has ruled out. Though Israel wants to see this war end and peace be found, skepticism remains that the PA is capable of forming an administration that doesn't threaten Israel's security.
Mustafa, a long-time ally and respected advisor to Abbas, is well-suited to taking this role. However, with much of Gaza in rubble, much of its population is either dear or starved and internally displaced. Meanwhile, Hamas is still in control of Gaza, and the PA is still deeply unpopular with Palestinians. Mustafa has a gargantuan hill to climb if he truly wants to have any positive effect on this situation.