Convergence. While not directly related to my benchmarking exercise, I read a forum post wherein a paladin states that in his Kara run, his meters show him doing up to 70% of the healing when running with a resto shaman and resto druid. He asks why the others are such slackers and what he should do.
The typical “first post” me too reaction was all-too-predictable: take them to task for it, take it up with the raid leader or the guild master.
Only several posts later someone started asking for more details, and recommended the OP to get more data before raising a fuss.
The question about whether a healer of a different class is pulling his weight, based upon your own damage meter addon (regardless of whether they actually are accurate enough or not, or whether there is some data synching between other players) is one which can be a lot harder to answer than just looking at a ranking.
First, there is the matter of knowing, in details, how the other classes heal. I currently write from a paladin’s perspective, my other healing toons’ highest level is a 29 shaman I haven’t touched since twinking became rampant in BGs… over two years ago. Oh, theoretical knowledge can help bridge the gap, especially if you have been playing and discussing with the same dedicated people for a long time, but first-hand experience is a different beast.
Then there is the matter of role repartition and how well your group / 10-men functions: if you have an excellent tank and the raid only takes little splash damage, the shaman for instance may be underused. The resto druid may have miserable effective healing scores and if you were to look into more detailed information than just your e-peen-boosting healing meter, you might see that he sits at 50% overhealing. And if you were using tools allowing in-depth analysis, perhaps it would suddenly appear that most of that overhealing (and loss of status on the healing meter) is actually due to you capping the tank spamming Flash of Light while he has Heal-over-Time spells ticking for nothing and going to waste.
Beyond that, you’d also have to get a good understanding of what exactly your Healing Meter addon records and how it gets attributed – A shaman’s Earth Shield for instance is usually recorded as healing done by whoever it is cast on instead of the shaman. Priest have heals suffering from the same loss of attribution. Paladins have it easy in this regard as we only offer single-target direct heals, which means we tend to miss the whole picture and how other classes are measured.
In short, regardless of whether any in-game Healing Meter is actually accurate in recording data from other players in your group or raid, I would definitely caution anyone from using just the top layer of information to pass judgment on how other classes perform. No matter the context, you won’t merely need detailed information on what is happening in the raid, what data is recorded and how it is being recorded and attributed, who was assigned to what healing duty, but also a keen understanding on how the other classes perform and what their own performance benchmarks should be. Meters are only a tool, and one which we should learn to use with the right dose of caution and grain of salt, lest we get caught up by ego and e-peen instead of the drive to become a better player.