I assume this is not a new idea but I have never seen it discussed. I suggest that much of the debate over nerfing content would be silenced if raids could (more finely) adjust difficulty for themselves.
Blizzard maintains that content nerfs are required when progression dips. This upsets some people. Others are upset that the nerfs don't come sooner and are not severe enough. So imagine the following system:
Two tiers of difficulty as we have currently (ignore LFR for the moment) 1. Normal, 2. Heroic. These remain the same, distinguished by new mechanics and/or differences in boss damage and health.
Now, for each tier, allow a raid group to adjust a sliding scale ranging from, say, 90% to 110% that adjusts
1.) boss damage and health figures,
2.) item level, and
3.) an achievement indicator specifying the setting chosen by the raid (when a boss is killed).
How does this solve the problem and satisfy both camps? On the one hand it allows players to control their own rate of progression. Raids that reach a road block can elect to make a boss slightly easier and hopefully get a kill (without having to wait for Blizzard to nerf content). They suffer a penalty in prestige and in gear quality but they will, I suggest, have a much better playing experience overall.
In fact, this also reduces the need for Blizzard to nerf content in the first place, since progression should be more consistent and stable over longer stretches of time. This should help reduce the complaints from the other side who hate to see content nerfed. You can attack Blizzard for nerfing content, but you can't really attack a group for admitting they need a little help to kill a boss and are willing to make the sacrifice to do so.
This also smoothes out guild progression. Currently many guilds clear content on normal but hit a roadblock when trying to transition to heroic. By allowing them to adjust the difficulty of normal up a little they can slowly increase their item level, perhaps making the transition to heroic raiding easier.
Perhaps including a minimum-number-of-attempts-requirement before allowing players to adjust the content down a bit would make sense.
Is this idea insane? It seems feasible to implement, but perhaps I am naive in thinking it would be a positive change. What do you think?