There's an overall trend, and it's not unique to Shaman, to look at the top 5 specs or so, declare those specs to be "okay", and everyone else is "crap". Not only is this mathematically silly, since you're taking the highest specs as your target rather than the average, but it means that you are setting yourself up to be permanently unhappy. You are, in essence, trying to create a paradigm that appeals to your desired sense of persecution.
A realistic comparison means you're looking at two things, with regards to class balance;
1> The average (both median, and mean) DPS as a target, and
2> The range from that average that the bulk of the other specs fit within.
If most specs are +/- 10% from the average, and we're at 9% below average, then we are competitive. Perhaps deserving of a buff, true, but not so gimped that we aren't able to compete. The specs that are way out of the normal distribution, either above or below, get discarded and ignored for those points. Those above are OP because of some unprecedented mechanic. Those that are way under, THOSE are the ones that aren't competitive.
If you're looking for your chosen spec to be in the top 5 before you'll be happy, your concept of class balance is flawed. The target is to be around #10 or so. That's the ideal.
If you don't like a spec, don't play it. However, if you're insistent that your spec be in the top 5 specs or so, either recognize that you're setting an unreasonable goal and will be disappointed, or be prepared to swap your spec every patch as needed.
---------- Post added 2013-03-08 at 06:21 PM ----------
To put this another way; check your relative performance on epeenbot; this gives you YOUR position, per log, relative to the distribution for your class. Then do the same for the guy you're comparing yourself to.
If he's ranking in the 90th percentile for his spec, and you're in the 70th, then a large part of the difference is that he is better than you are. He may outgear you. He may just be a better player than you are. But it's a difference that has nothing to do with the spec.
Besides which; if you're not performing in the 90th percentile for your spec, then there's room for improvement for you, as well.