Made this deck last format. Make sure to get that Fliptini when it comes out if you like this deck.
This deck is purely about speed. 15 Grass is waaaaaay too much.
-6 Grass energy
I see the healing strategy you're having, and I haven't done that before. Use Revives in case of sniping, or for those Reshy's Zekroms, or anything that can OHKO.
+4 Revives.
This deck is also very prone to trainer lock btw. More supporters instead of trainers, though the speed makes this hard. Also, pluspowers are your friend. Next, why Reversal and not Catcher?
-4 Reversal
+4 Catcher
Torkoal isn't really needed. It takes up too much bench space, which could be used for something else. Haven't tested it with Cleffa, but I'll leave it to you. Bench space is tight with 4 Volbeat, and preferably either a free retreater or else a second Illumise, as it is your main attacker.
-2 Torkoal.
You have now 4 extra slots. Pluspower pluspower pluspower. Using one and getting two heads(Which is the medium), you can KO a Phanpy, Tepig, etc. That's your goal, really. Speed and smacking.
+4 Pluspower.
Also, I'll be honest. Pokeball isn't needed, and Recycle just is a no. Too flippy for not enough reward.
-4 Pokeball
-4 Recycle.
Try adding in some PONTs for new hands, or else Copycats or Bianca... Depends on your playing style. Plus, with supporters, you'll be less damaged by Trainer Lock.
+4 PONT/Copycat/Bianca
Finally, this gives you four extra slots. I'd suggest either a couple Communications and some Cheren's, or else Defenders if you're aiming for a more survival-ish. Otherwise, Energy Retrievals also help with the lower energy count. If you want to put Recycle or Pokeball in, I'm not a fan of them because you're flipping enough as is, but it's your decision.