A number of things wrong with that data sample.
1) You're only looking at top ranks. Just because you're not top doesn't mean you're not worth taking.
2) You're looking at a sample of data from a raid which has been out one week. Not enough data to make any comparisons at all.
And that's just the obvious flaws the data you linked. SimC might not be the best data to use but neither is WoL. They are not tools for class comparison. They are tools to help you better yourself by looking at your gameplay in a greater depth and working out how to improve it, which many many people don't seem to understand.