This Amoongus is outclassed by Roserade in every way, and Roserade is a terrible card, you can only guess how bad this makes Amoongus in my eyes. I really don't understand why it is receiving any hype. We have already seen that decks centered around special conditions are bad, all the attackers special condition decks can utilize are too frail, stage 1's, and require Trainer Lock to function properly. For this combo to function for one turn (one knock out), you are going to have to get out two stage 1 lines, and in most cases, a Vileplume is desired, if not needed. This is true for Ninetails, Leafeon, and Zebstrika (lol).
Decks centered around Amoongus will fail, because other things can hit for the same amount of large damage, consistently, and take a hit or two because the main attacker of the deck has more than 90 HP. This card also falls short of being a good tech, you will need a 2-2 line for it to work "consistently", so it takes up four deck space, and a benched space (or 2), to give your opponent a small inconvenience, assuming they don't get a lucky coin flip or hit a switch. It is also worth mentioning you are only going to be able to get this combo off 1-2 times a game on average. Devolution Spray, ah, no, even if it were to be printed without a text change of some sort (which is unlikely), it would be bad, because it would eat up 2-3 deck spots, for a card that can only benefit one aspect of your deck. At least with Roserade, you already have Rainbow Energy in print, no ifs there, and your Rainbow Energy can be used by your other attacks. It is also worth mentioning that Roserade can function as a back up attack. I'm sorry, I'm not seeing it guys.