If a meld is unsuccessful, it currently takes us back to the menu, where we have to re-select the item from the list, select the materia from the list, then blow through two warning prompts to try again. It is not uncommon to do this dozens of times in a row for the same meld.
It would be nice if when a meld is failed, so long as you still have the same materia and catalyst available in your inventory, that it gave a prompt asking, "re-attempt the same meld?" with the meld window in the background. If not that, at least keep the item and materia selections saved and bring us back to that point instead of square one.