Recent comments and posts have gotten me thinking about BC again. Specifically, what content were people seeing? My sense was always that just about everyone who had the slightest desire to do so had done some heroics. Similar for a place like Karazhan, especially when the attunement requirement was removed. After that, I feel like the numbers dropped off by a lot.
I wish I knew for certain, because if there's one thing I've learned, it's that my sense of things is not a particularly accurate measure of the overall situation. Hell, in vanilla I thought that raiding, at least at the Molten Core and 20-man level was accessible. But supposedly not everyone had done MC. I say supposedly because I don't remember what the numbers were on that, or whether I even saw them ever.
I'm sure Blizzard has these numbers. I want them! More specifically, here's a breakdown of what I'd like to compare.
Class distribution for each expansion
% of characters at max level and % of accounts with a max level character
How many people regularly ran the high-level dungeons in vanilla, comparing these with heroics in BC, LK, and Cataclysm
How many people killed a boss in any raid in each expansion
Wandering off from this, I wonder how much accessibility really matters. If content is made easier/simpler to get to, but not necessarily to beat, do more players do the content? Or are those who are driven off by an attunement not particularly interested in it, and would quit it soon anyway? Could barriers to entry actually be doing people a favor, by keeping them out of content that they would not enjoy enough anyway? I wonder who has more fun and is a more stable subscriber, the former raider or the non-raider.