Thunder Wave needs to get a secondary slash with Psychic on the main set, it's part of the reason Slowbro is so annoying to deal with in OU. Thunder Wave ruins offensive checks like Lati@s, Dragons, Weavile and anything unfortunate enough to switch into that doesn't have any ability that negates its effects. Even Rotom-W doesn't like taking a Thunder Wave because it kills its Speed stat, and can cause it to get haxed down the line. It's too powerful of a move to be placed in AC.
You should look into testing Specs Slowbro in OU. In addition to being a check to Physical Attackers and having Regenerator, it hits like a truck and has Flamethrower to mess up Ferrothorn (but you probably want to use this thing on a rain team so...) Nothing really overshadows it imo, I think you should give it a chance. (I'll try it out on the ladder and get back to you).
small nitpick but
Calm Mind Latias likes to get burned (what a freak)
Nothing likes to get burned. A burn is an extra 12% damage per turn, effectively negating leftovers, forces it to recover more, and if Latias so happens to be in the sand, god help her soul.