Alright.
You can listen to me if you want. You can call me an idiot, you can say I'm not being constructive, but I do know some of what I'm talking about, so hopefully you'll take some my suggestions into account. You may also completely ignore me. It doesn't affect me one way or another.
This deck is all about speed, consistency, and fast, hard hitting attackers that can do a lot of damage while taking quite a beating themselves before they go down. After they do go down, you'll have a Ho-oh standing by to pop right back up with more energy and start pounding away at them again. That being said, the attacker line is somewhat lopsided. I understand why Rayquaza may be appealing, but 40 early on is not very much in today's game (despite a few donking scenarios) and even though the two discarded cards can help, it's not worth a near useless attack to get them in the discard. The 4 Rufflet also needs to go. Again, I completely understand the premise of using it, but this deck doesn't like set up attacks, it likes high damaging attacks and it likes them very early. Running 4 Ultra Ball should be completely fine for searching and discarding Ho-oh's. I do like the inclusion of Sigilpyh though; it brings quite a bit to the table against decks that don't have much of a non-attacker option. I might cut it down to one, but it's really up to you (that's not a major issue at the moment).
Now, for adding more attackers. I know you have Sigilpyh as a counter to Mewtwo, but Mewtwo doesn't just have to be a counter to himself; he's a fantastic main attacker also. He puts on the early game pressure that this deck so desperately loves, craps on decks that have a difficult time swarming Mewtwos of their own (such as Keldeo/Blastoise), and is just overall fantastic. I don't think this deck functions well at all without at least two of it. For another attacker, Terrakion NV is great. It can do a fast 90 damage with the use of Energy Switch, it really hurts Darkrai decks, and is again an overall great attacker. It also helps set up the seven prize scenario, where your opponent has only taken five prizes but now is faced with KOing an EX.
Now for the trainer line. To start, I'll dive right into the topic that you don't want me to talk about: supporters. I normally would not argue with someone's final decision with their deck (especially considering you've put up quite a fight for this as I've seen), but supporters are a main focal point for any deck, and running only 4 Juniper is something I can't stand by and let go. For starters, scrap the Xtranciever. It's extremely flippy and using a card that is directly designed to add consistency to a deck that requires a flip is extremely redundant and there is almost no point to it. I know you don't like Random Receiver, which is why, in fact, I'm going to suggest not using any kind of Supporter Search at all. Instead, as has been said, run more supporters. While 4 Juniper may seem like enough, it's very difficult to draw into a 4 of-card often enough, even if you are running 4 Xtranciever like you are currently doing. Here's what I propose the supporter line be:
4 Professor Juniper
4 N
3 Bianca
2 Skyla
This is 13 supporters, which doesn't feel clunky but doesn't feel skimpy on the supporters also. It also forgoes the use of Random Receiver, meaning you never have to worry about hitting a supporter you don't want at a bad time. While you may want to Juniper often (to get those Ho-oh's in the discard), the other supporters help to give you a chance when you don't have access to the Juniper. N and Bianca both do a fine job of giving you some more/different cards, and will eventually help you get the Juniper and everything else you may need. Skyla is nice because it search out your deck for any trainer you want and can snag the last card of a big combo for you. Energy Switch, Ultra Ball, or even a Juniper for the turn after if you're lacking in cards. Again, I know you really don't want to run more supporters, but you won't be getting the cards you need often enough with only 4 Juniper.
For the items, to start, take out the Enhanced Hammer. It's super helpful in many situations, but no matter how good it may be, it IS situational, and as a general rule of thumb you want to focus on the decks main strategy rather than include cards that may help you at random times. You should also take out the Pluspower, as this deck has a plenty high damage output already and doesn't need Pluspower to boost that. It's nice for Terrakion against an Eviolited Darkrai, but Tool Scrapper does the same thing in that situation. Speaking of Tool Scrapper, I would cut it down to one because you can now search it out with Skyla if you really need to, and your probably not going to need to scrapper away more then two tools a game unless it's against Garbodor, who is very rare to see these days. You should also bumb the Energy Switch count up to 4 just to make sure you can get those attackers running ASAP.
For adding trainers, the one MAJOR card that needs to be added is Pokemon Catcher. This is one thing that is an absolute must and cannot be left out. Argue all you want, but the simple fact is that it's probably one of the best, if not THE best card out there. From stalling your opponent to grabbing a KO on a damaged Pokemon that just retreated to KOing important support Pokemon like Eelektrik or the pre-evolutions of Hydreigon and Blastoise, this card has so many uses that I cannot think of one argument not max it out in every single deck except for those that run Sableye to re-use Catcher. This, along with the Supporter count, is one thing your deck has to change to function well. Ignore me if you wish, but you are going to learn the harsh truth of that as soon as you go to a competitive tournament. Anyway, for other trainers to add, a nice addition is Super Scoop Up. It allows you to get damaged Pokemon off the field, get a Ho-oh of the field (maybe one that you used merely as a source of energy for Energy Switch) and has a variety of other uses. In fact, many lists that I've seen run 4 Super Scoop Up because of the amazing synergy it has with this deck. It does have a coin flip, so it's not extremely reliable, but many times you may only need 1 or 2 heads during a game to accomplish what you need to. Lastly, add one Computer Search. Do I need to explain this? Getting any one card out of your deck AND getting to discard some cards with it is literally better than any effect of any trainer you have in this deck.
And finally, the energy. Instead of ranting more, I'm just going to dump a list of the energy line that works with the deck that I've "created" for you:
4 Double Colorless Energy
3 Fighting Energy
3 Psychic Energy
1 Grass Energy
1 Fire Energy
1 Water Energy
1 Lightning Energy
1 Dark Energy
1 Metal Energy
1 of each energy works fine, and while it may seem very low to you because of your extremely high current energy counts, you really don't need more (you'll find this is true after testing the deck for a while). The DCE is included to power up Mewtwo and many of your other attackers, such as Sigilyph and even an emergency Ho-oh if you need it.
Since I've given a lot of changes and you probably don't want to go back through them to try and change your decklist, I'll give you the list that I've had in mind while writing this:
Pokémon (9)
3 Ho-Oh EX
3 Mewtwo EX
2 Terrakion NV
1 Sigilyph DRX
Trainers / Supporters / Stadiums (35)
4 Professor Juniper
4 N
3 Bianca
2 Skyla
4 Ultra Ball
4 Pokemon Catcher
4 Energy Switch
4 Super Scoop Up
3 Switch
1 Computer Search
1 Tool Scrapper
Energy (16)
4 Double Colorless Energy
3 Fighting Energy
3 Psychic Energy
1 Grass Energy
1 Fire Energy
1 Water Energy
1 Lightning Energy
1 Dark Energy
1 Metal Energy
Keep in mind this very flexible and you may include whatever extra stuff that you like while cutting things down that you don't like. It summarizes all of the cards I mentioned into one, clean list.
That's all the info I have. Keep in mind none of this was meant to be insulting or flaming in any way and that it is an attempt to give constructive criticism. If you have any questions, feel free to ask and/or PM me. I'd also be glad to play against you sometime on PTCG if you ever want testing. I hope you take the time to read this (as I spent considerable effort typing this out) and I hope this helps you in whatever tournaments you play in!