Where to begin...? (I'll only say a little bit for now, as there is a lot to cover on the grounds of battling, it is very late in the evening over here, and I am about to log off for the night.)
The team is decent. It has good Pokemon, but as a whole, they don't work very well together; only two Pokemon benefit from Sandstorm (once it's been set up), and the Zoroark/Toxicroak combo works better outside of weather such as sandstorm (not that there was a sandstorm when the combo was destroyed, but it's worth a mention).
Every team needs a central strategy (whether the team benefits from weather or not doesn't matter, but OU tends to have a lot of weather nowadays). If you plan to make a sandstorm team, consider placing Leftovers on certain Pokemon as well as adding Pokemon immune to sandstorm (a.k.a. Rock, Ground, and Steel types).
There's a lot more to be said here, but I'm running out of stamina, and I'm going to bed. I'll tell you more tomorrow.