While I like the sentiment behind the suggestion, I do not like the suggestion.
There should be incentives to include players in content, but this suggestion is too extreme. The fact that it would be a non-repeatable bonus is probably the main problem, with the ‘greater rewards for sub-optimal play’ being a close second.
In the current form, this suggestion wouldn’t work, as ‘elite raiders’ would not in fact include inexperienced players, they would instead (if the rewards from raiding were good enough) create alts and run them to the raiding location to fulfill the same function. If this bonus was account bound, you would solve some of this issue, but then you run into the second pitfall: it is non-repeatable.
Perhaps you would incentivise new players being exposed to new content, but eventually you will run out of a reliable stream of ‘new players’ that will provide this added bonus. This will change the already toxic “zerk or kick” problem into a worse problem: “bonus or kick”; which would exclude players who chose to learn how to run the raids properly and enjoy this content in favor of those who may never run the content again. It is possible new players exposed to raids may enjoy them, but their experience that made them decide that is flawed because they received extra rewards in that first run. It is not wise to alienate the fanbase of certain content in favor of players who are not guaranteed to continue using that content.
Lastly, rewarding sub-optimal play over optimal play is anathema to any game design I have ever heard of. It would foster poor practices in the playerbase and likely lead to more toxic community interactions. This is not to say that there should be no rewards for the less skillful or commenting on whether raid rewards should be accessible from another method (that would be off-topic), but rather that degrading the experience for those players that have learned how to do something properly — just so that others who have not invested the same amount of time and dedication can receive the same rewards — is a bad choice for the longevity of any game.
If a player wants a reward from a certain type of content, that player will do what it takes to get that reward. It is unfortunate that some community members may exclude others from certain groups, but most any form of incentive will not truly correct this behavior. Any incentive system will be gamed by those elitists to their own benefit and the net result will likely be the same: inexperienced players will still get the shaft (by those elitist groups). The end result is those elitists will gain the bonus just as often as the inexperienced and there will be no real reason to include the inexperienced, so long as there is some work-around to achieve the bonus (which there almost always will be).
I am not saying this is right. I am not saying that I don’t want incentives for including more of the population into difficult content. I am saying that players that purposefully exclude others will continue to do so, as is their prerogative in the game.
I think Gw2 has a great community overall, and there are plenty of guilds, groups and players that are supportive and inclusive. There are, of course, elitists in the game, but overall I think the percentage of these players is far, far fewer than in other contemporary games.