I was reading a post on the official forums about potential changes to the warrior class. The poster included the line that the rage system should be changed "because it's an outdated mechanic". Now I'm not sure that I buy into the "outdated" part - sure it's not as funky and cool as the rune system, but it's been around as long as the energy system, or the focus system, but not as long as the mana system.
Nevertheless, I think the rage system has some quirks all of its own that bear some thinking about.
1) Warriors (and bears, obv) are the only class which starts an encounter at zero resource.
Every other class starts at 100% resource, while we have to earn ours first before we can use it. This causes problems incredibly often - how many times can I (a new tank in 3.0) remember avoiding the first two incoming attacks, and so essentially being at zero resource for the first 6 or 7 seconds of a fight? With my avoidance (including miss) of say 40% (can't remember the number offhand, but it's above that) then 4/25 of the time I will avoid the first two boss attacks, or 16% of the time.
There are some things you can do - request an MD (but you may not have a hunter or rogue, or the daft dpser may MD the mob on the wrong target - this happened twice last night), pull with heroic throw, hit bloodrage, or charge - but these all have their own drawbacks or cooldowns, and are basically not optimal. Certainly a "body pull" is just asking for trouble, and a lazy tank on the pull is generally one who will wipe the group.
2) Rage starvation in easier content
Your dps' ability to generate threat scales with their gear. Yours declines with your gear. At some point the two graphs will cross, which is why you get stupid wipes in silly easy instances.
3) DPS is balanced around infinite rage
I can't do competitive (ie competitive for a non-DK tank) dps unless I have infinite rage and am able to HS on every swing. Apart from the obvious point that doing competitive dps requires me to press the buttons so fast I should basically bang my head repeatedly on the keyboard, it seems that Blizzard balance our dps around these horrific rotations which require constant heroic strikes.
In a normal raid environment I am concentrating on moving the boss around and not dying. I just don't have enough hands to hit 2 buttons a second, and therefore my dps falls off. I think if I bind HS to all my abilities this might help, and so I've begun this process.
Interestingly, in infinite rage scenarios we are at a significant advantage over DKs - we can use any of our abilities (cooldowns permitting) whenever we want - we don't have to have runes available of the right colour or sufficient runic power. While the DK resource system is fun and interesting, it is very hard to monitor effectively during a fight and seems to lead to some very technical rotations.
I hate PvP and am very bad at it. But when I do venture into the arena, the swine just ignore me and nuke my partner. I can charge/intercept once each, and then I am reduced to trudging dispiritedly towards the enemy doing white attacks to gain rage whenever I am fortunate enough to be in range. Perhaps this is a skill thing rather than a resource thing.
So, to sum up, I quite like the rage system, but it has many drawbacks. The possibility of zero rage on a pull is the most important I think, because this does cause deaths in a raid environment and is a really unpleasant sinking feeling when it happens.