Feanor Self-Important?

[Aredhel Idril Telcontar]

Do you think the Valar could not have handled the situation? They obviously could (and did later on)

The War of Wrath only happened because Earendil managed to sail to Valinor and beg for help. The Valar would not have interfered unless Morgoth would have threatened Valinor.

Did the Noldor save Beleriand? No.

When Morgoth first attacked the Sindar, they were not able to protect themselves. Feanor burning the ships (like Phantom said) drew the attention of the orcs from Cirdan. However reprehensible that act was, it did turn out for the better.
If the Noldor would not have come, Beleriand would have been overrun. It's obvious.