I highly doubt the Sovereign sees much Standard play, unless there are decks that can consistently gain tons of life. One archetype that comes to mind is the Mastery of the Unseen deck that popped up awhile back. Along with Whisperwood Elemental, flipping over a Morph creature could gain you ridiculous amounts of life, but that in itself wasn’t really a win condition. Imagine manifesting this as a 2/2, and flipping it for 4WW at the end of your opponent’s turn when you’re over 40 life. Good games. That’s about the only way I see the Sovereign making serious competitive headway.
While the Sovereign will take a major price point hit, I’m happy to see it become much more accessible. Sylvan Scrying needed a new printing, too, so while this will make the previous printing a bit less valuable, there should be enough demand that this will remain a valuable uncommon.