I accidentally disenchanted a piece of gear while getting fleeting arcane manifestation points, and didn’t notice until I spent the soulbound fleeting arcane manifestation. The restoration requires the fleeting arcane manifestation, and of course I can’t get any more until the next reset, so in such a case you can’t restore the item for a week. Assuming that I won’t actually get an extra fleeting arcane manifestation if I spend one on an item restore, would it be more reasonable to not require the fleeting arcane manifestation for the restore?
That’s a question for the developers, I’m afraid. You’ll want to create a new post over in the Support Site Feedback forum.
They’re never going to allow a restore that completely reverses all effects of the original deletion or destruction without requiring all of the products of that destruction or deletion. If you sold the item for gold, you will always need the same amount of gold to “make it right”. Likewise all outputs from disenchantment have to be on-hand to reverse the disenchantment.
And if you lose an item to a quest, forget about restoring it, because there’s absolutely no way to reverse quest progress. (For instance, giving a trinket to an NPC to advance the quest to get a mount.)
If you could disenchant an item, consume the +skill points item, and then restore the item to get another crack at another +skill item, that would be exploitative.
They’re never going permit anyone to “come out ahead” in the restoration process.