A lot of wining comes from knowing your deck and knowing how to play in a given situation. That's why most pros can pilot a ham sandwhich to victory.
I do like this deck, and tried it for a little bit. I was on the yisan version, but imo it suffers from not being able to get devotion/prophet online in time. While backbreaking when it happens it can be fragile. Prophet on its own will not win a game and applies little pressure. It's basically a combo deck. Prophet+nykthos+follower+big scary thing. While you don't always necessarily need all 4 pieces to win, if you "go off" then your opponent has a hard time coming back.
Overall i think it's fine and if you're good at piloting it will serve you fairly well. There will just be games where you can't make it happen because you didn't get a piece of the combo.
As far as aetherspouts, i think it's a bit mana inefficient, normally you only need to tempo your opponent. I like the way the deck interacts with retraction helix. Helix, on a caryatid with a follower or two out, will do almost as much work as aetherspouts in this meta and it's a lot easier to cast.
I adapted the play style you're talking about and moved to a more proactive strategy. Temur for me has been pretty consistent. Almost every card in the deck is a threat. Nothing is back breaking, but everything is "must answer". You also get access to stubborn denial while only 1 less than negate is much easier to manage. And denial just won't work in the UG deck. It also gives you access to other lines of play not available to UG. You can't ever burn those last 3 hp if the board gets clogged, or remove a planeswalker easily. Also, i get to cast storm breath... people hate that.
My temur list atm : https://deckbox.org/sets/754821