With each expansion, we all take part in the following gear treadmill:
- Level up - acquire gear from quests to use in dungeons.
- Run scenarios and dungeons - acquire gear from bosses to use in raids.
- Run raids, PvP, world bosses, and other forms of endgame content - acquire gear from all of that to use in new tiers and at higher difficulty settings.
- New expansion - reset and repeat.
Wouldn't it be cool if everything you did rewarded you with a few points you could distribute somehow to gain power in various ways (like Paragon Levels do in Diablo 3)? Playing through any type of content could give points, but based on the difficulty, time required, and so on should reward more. Especially when the content is current.
Then, once the new expansion hits and you've been a dedicated player throughout the previous one, you will still keep some amount of bonus power that is only available to you and others who worked just as hard as you did. Not too much power as that would punish less dedicated people too much. But enough to make you feel like all the hard work was worth it, and that your account becomes more heroic with every passing year.