I like your team, it has a nice feel and overall seems fairly balanced, albeit being more on the offensive side.
To start out, Charizard Y should probably have Fire Blast over Flamethrower. I know it's an argument of Power vs. Accuracy, but on a set like this, You want as much power as possible. Also, Dragon Pulse generally isn't the best coverage move. It hits dragon super effective, yes, but a Fire Blast in the sun will be doing almost as much, and Dragon Pulse won't be doing substantially more, enough to score you any KOs. You're much better off running Focus Blast if you want a fourth attack, or something like Roost or Substitute for helping you sweep.
I'm going to assume that those EVs on Heracross are a typo, but just in case they aren't.. You'll want to run max Speed and Attack, because you are a physical Choice Scarf set, and put the 4 leftover into a defense or HP. You'll also want a Jolly nature to max your Speed.
For Rotom-W, Pain Split is a nice option for a fourth move over Confuse Ray. It's very useful since Rotom-W has low base HP but high defenses. Also, I'd recommend running Leftovers over Lum Berry, as it gives much need recovery to a defensive pokemon. Speaking of it's defenses, I'd recommend making Rotom-W Bold and moving those EVs from special defense to physical. Since Heatran has special defense investment, physically defensive Rotom-W is a great complement especially because of its typing.
Last but not least, if you're looking for a Spinner (which you do desperately need), Starmie would serve as a replacement for Keldeo. It's also a Water-type special attacker, and it has Thunderbolt so you don't have to run HP Electric. It also has options for Recover and Psychic STABs, so it's quite versatile.
Overall, nice team, just needs a few adjustments.
EDIT: Added that Rotom-W should be physically defensive.
