[the phantom]

One thing people seem to be forgetting is that the Noldor had to get to ME as soon as they possibly could. They actually arrived a bit later than they should have, a result of their march being hindered.

Why did they have to be back in ME immediately? Well, do you remember what was going on back in Beleriand?
From the Silmarillion-

and they issued from Angband's gates under the clouds that Morgoth sent forth

But the Orcs came down upon either side of Menegroth

and they plundered far and wide; and Thingol was cut off from Cirdan at Eglarest

But the victory of the Elves was dear bought. For those of Ossiriand were light-armed, and no match for the Orcs, who were shod with iron and iron-shielded and bore great spears with broad blades; and Denethor was cut off and surrounded upon the hill of Amon Ereb. There he fell and all his nearest kin about him

the Orc-host in the west was victorious, and had driven Cirdan to the rim of the sea

Morgoth had started his world conquest machine up the instant he got back to ME. At the point where I stopped quoting, the only refuges left were the Havens and Doriath, and the Havens were about to go down to defeat. Thingol and Melian shut themselves in Doriath and she put out her girdle of protection. In other words, the world was pretty much open for conquest (except Doriath, and how long would it last if Morgoth gave it his 100% concentration and no one else was distracting him).

Things looked pretty bleak, but here's what happened-

In this same time Feanor came over the Sea in the white ships of the Teleri

But the host of Morgoth, aroused by the tumult of Lammoth and the light of the burning at Losgar, came through the passes of Ered Wethrin, the Mountains of Shadow, and assailed Feanor

The Noldor, out-numbered and taken at unawares, were yet swiftly victorious; for the light of Aman was not yet dimmed in their eyes, and they were strong and swift, and deadly in anger, and their swords long and terrible. The Orcs fled before them, and they were driven forth from Mithrim with great slaughter

There the armies of Morgoth that had passed south into the Vale of Sirion and beleaguered Cirdan in the Havens of the Falas came up to their aid, and were caught in their ruin.

Evil indeed were the tidings that came at last to Angband, and Morgoth was dismayed. Ten days that battle lasted, and from it returned of all the hosts that he had prepared for the conquest of Beleriand no more than a handful of leaves.

Feanor saved Beleriand, and pretty much the whole world from Morgoth. If he could've arrived sooner, maybe he could've saved many more of the innocent elves of Beleriand who were slain in battle.

And note what the burning of the ships accomplished. The burning was a huge factor in making Morgoth's forces turn their attention away from Cirdan and Beleriand and attack the Noldor ("and the noise of the burning of the ships at Losgar went down the winds of the sea as a tumult of great wrath, and far away all that heard...", it was the noise and light of the burning that attracted the Orcs). If the ships wouldn't have been burned, the orcs likely wouldn't have learned of the Noldor's arrival until later, so they very possibly would've broken through and taken out the almost defeated Cirdan at the Havens.

So as you can see, even the most insane of Feanor's actions was the best conceivable way to bring about good in the world.

If Eru's plan was to have some powerful elves go back to ME, who would he send? The Noldor. They were the greatest warriors.

What is the only way the Noldor would go back? If they wanted to go.

How could you get such a large group of people to want to go? Put a fiery desire to leave in the heart of the greatest persuader and orator ever to live.

When did they have to be back? As soon as possible. The world was under attack.

How could they get there that quick? They would have to be hindered as little as possible on their journey and taken over the sea in boats.

They were refused the use of the boats but the timetable hadn't changed. How do you get them over the sea in time now? They must steal the boats.

Because of the battle and the wrath of the sea delaying them, their arrival is almost too late to save Beleriand from the Orcs. How do you get the Orcs attention as quick as possible? You light up the sky with a huge noisy burning.

Feanor did what needed to be done. His heart could sense the greater good and the big picture, and he was able to look past the means to the ends and do what had to be done to bring about the best possible result. He was a tool of fate.