................... sombra is far too weak to be a threat to the alicorns. he is powerful but they easily overpowered him a millenium ago, likely when he had the crystal heart. while luna's trength may not have grown, Celestia is older, stronger, and more experienced tahn she was back when sombra reigned the empire.
he would be pulverized.

3767977 they used the elements of harmony on him. No one that disharmonises the world could stand up to that. But before they used the elements he stood against them, Sombra is much more of a threat than they gave him credit for on the show.