While the number of people who use the forums is small... and the number of people who would be counted as PvPers and raiders is small... the people who even semi-regularly participate in the raiding aspects of the game tend to have the most "trickle-down" impact on the game.
In terms of the impact raiders have on the community, let me fire off a few examples...
> Raiders are the most likely people to use the Auction House. Their "money" often goes toward the gear and consumables they need for group activities. A raider (playing a hunter) is much more likely to even go looking for Light/Fire Oils, Bow Chants, and Focus Potions. A raider is much more likely to think about using various things that might be overlooked by others. And, guess what? Raiders are the most likely people to (by extension) support the "economy" of their server.
> Likewise, raiders are much more likely to make full use of the crafting system. They want the good gear and consumables. So, that is going to create natural demand for crafted items. Yes, other people do use the crafting system... but not nearly as much as someone who needs to keep up their crafting to support raiding habits... and by extension, their friends are encouraged to keep up their crafting to support their raiding friends.
> Raiders are the ones most responsible for a lot of the good items that make their way to the Auction House. All those Star-lit crystals on the AH didn't just magically appear. You don't get them by RPing or questing (well, not yet anyways). You get those kind of items to drop only by running 3, 6, and 12 man instances.
> Raiders are the ones who encourage the building of a solid network of "friends" within the community. There is just something about "fighting, bleeding, and dying together" that builds friendships... in ways that other methods don't even compare. You are able to make that "connection" much better via raiding. Granted, some raiders can be jerks... but I would say easily 90% of them are great folks... if you don't mind putting up with a little coarse language and crazy antics.
> All other aspects of the game benefit from having a healthy raiding community. I dare say that raiders are much more likely to discover the "fun" aspects of the game... like RP, music, crafting... even delving more into the quests... because raiders want to learn the mechanics of the game so as to discover how best to play their characters. Even raiders need time to just chill out and do non-raiding stuff. Example: There was a really great Guardian who used to play on my server (some may know him as Horthell) who also loved to mess around with the music system.
> Raiders are the most likely people to spend [real] money on the game. They have the most incentive to do so... if only to maintain their subscription.
> Raiders are the most likely people to have greater knowledge about the game... and be able to pass it along to newbies... thus, adding more people to the "raiding population."
Now, don't get me wrong... I am not saying that other people don't do some or all of the things I listed. I am simply saying that raiders have the most natural incentive to take full advantage of all aspects of the game.
And, I dare say that those who are voicing discontent with the LACK of adequate group/raiding content is steadily growing beyond just the more active raiders... even the some of the people who are more the "average Joe that only dabbles in grouping" are starting to speak up.
As I have stated before... for the first time... Helms Deep brought us new content that has not really offered decent group or solo friendly content. At least with Riders of Rohan, we had Hytbold initially... and the Erebor instance cluster. Not everyone thought they were the best... but it did give decent solo-friendly progression (Hytbold) stuff to do at the level cap... and Erebor at least attempted to give us some instances capitalizing on "The Hobbit" interest.
Helms Deep brought us the trait trees... which has had mixed reviews depending on who you ask... but (IMHO) fell short on even doing what Riders of Rohan delivered. So, now, not only are the "raiders" unhappy with the LACK of good group stuff... Big Battles would have been so much better with a few tweaks... but, there is not much for the solo guy to do once you hit the level cap. The solo guy doesn't even have decent repeatable quests to do to get more Western Rohan barter tokens beyond war bands.