With Hydregion, you could get rid of Dragon Rush and Thunder Wave and replace it with Dragon Breath because the accuracy isn't great and just imagine a Sand Attack. Also, there's a possibility of the opponent getting paralyzed. You should put a steel type move in there to protect yourself from fairy types because that's a very big threat to a dark/dragon type like Hydregion. I recommend Flash Cannon because it's one of the only 2 he could learn. It's better than it in my opinion, but it's called Steel Wing if you want to consider it. Flash Cannon is given to you by a guy in Kiloude City and Steel Wing is a prize in Battle Mansion. Also, I could see Mild and rash as better movesets, but if it's too hard to get, don't do it. That's all I have to say about Hydregion.
Scizor is actually pretty good on the other hand. The only thing to worry about is its horrible weakness to fire, but there isn't much you could do about that unfortunately. Sorry, I looked and the only thing is Sandstorm, but it's just a waste. The only other thing I can recommend is the ability. The best ability is probably Adamant, but Lax is the second best. Again, you don't need to go through all of the pain with getting it with a good ability, just so you know I brought it up.
