Here's a log from ScrubBusters:
http://www.worldoflogs.com/reports/r...e/?s=389&e=831
It shows Imperial V heroic and from this you can see each classes burst.
We can see that Boomkin seems to have the highest burst by far, followed by Death Knights and then Warriors and Rogues.
In comparison, the classes with the least burst were: Warriors / Rogues.
This shows us that burst is heavily dependent on procs and the only real way to judge class burst is to unequip trinkets and take off your weapon enchant.. I don't have access to such things for all classes but as the log shows, there can be 100k difference in burst DPS when looking at the rogues and I doubt any gear advantage is big enough to explain that sort of differentiation.