Nils made a couple of posts on this subject already which got me curious, especially this one. After playing some of my own low-level alts in the past couple of days, I can only confirm that he's not exaggerating. The power inflation at low levels is absolutely insane at the moment.
Example one: I took my level thirty-one protection warrior out to explore and do some mining. In Desolace I aggroed three mobs that were red to me while trying to get to a node. I don't remember the exact level difference, but I believe they were five or six levels higher than me each, maybe even seven. I fought them for about thirty seconds, by which point I decided that this wasn't going to lead anywhere as I was losing health faster than I could reduce theirs, what with the high level-imposed miss chance. So I retreated, ate until my health bar was full again, and then killed the same three mobs comfortably one by one.
Now that just strikes me as wrong, and not just because I couldn't have done that "back in my day". The colour scale is supposed to be an indication of difficulty: grey mobs are trivial to beat, green ones are easy, yellow means medium effort is required, orange means they will be a reasonable challenge, red should be near impossible. At the moment it feels more like everything up to yellow is trivial, and even red mobs only require a couple of button pushes. It's just silly.
Being a warrior, I also found that my rage generation had gone through the roof. Even when I was fighting mobs that died in two or three hits, I was gaining rage faster than I could spend it and as long as I kept fighting my bar was pretty much perpetually stuck at one hundred. So much for rage "normalisation"...
Example two: I noticed that my rogue was getting close to level forty and decided to hop into a battleground before he'd level up into the next bracket, both for fun and to have a shot at the G.N.E.R.D. Rage achievement. I ended up in a WSG match in progress where fifteen of the twenty players were rogues... and they were all one-shotting each other. It was pretty ridiculous really, and I got my achievement very quickly - when people die in one hit, even if it's you sometimes, that leads to a lot of honourable kills. However, gameplay-wise that match was a complete and utter failure. Nobody could run the flag as they would get one-shot the moment someone managed to hit them. There were actually healers on both sides, but they were unable to make a difference in any way, as people went from full health to dead in one global cooldown. I had no urge to go back for another match.
Example three: On the same rogue, I decided to queue for a random instance instead and got into a Scarlet Monastery - Cathedral run. Our tank was a protection warrior on the lower end of the dungeon's level bracket, but he just barrelled through the place like a force of nature anyway. He couldn't always hold aggro, but that seemed to make little difference. The AoE damage from his Thunderclap spam meant that he was top of the damage meter too, as nobody else had any AoE.
Inside the cathedral itself we cleared out the front half of the building in a manic free-for-all as people just aggroed more and more mobs without any negative consequences. Then the warrior ran up the stairs and charged Mograine. "Oh no," I said in chat as the entire second half of the building aggroed on us at once. I hit vanish, fully expecting us to wipe, but the warrior used his Thunderclap spam to get them all on him, and even though he was tanking a dozen mobs three levels higher than him at once, he lived through it quite comfortably. I rejoined the fight when it became clear that he wasn't going to die and we finished the instance.
Once again it was kind of funny in a "this is amazing compared to what I'm used to" kind of way, but at the same time very sad, because from the looks of it this is what all low-level dungeon runs will be like for at least the next two months. Once Cataclysm gets released... who knows? The developers actually don't seem massively concerned, though I also found this quote from Kalgan, where he says that "nobody should be one-shotting at any battleground level" and that those issues will be addressed.
Only a little more than a month ago I said that running Gnomeregan is not like running heroic Nexus in ICC gear, but it seems that even that isn't true anymore now. I'm trying to be positive, but the whole situation does leave me with an uneasy feeling in my gut. After all there's little point in having all these cool abilities if we can just kill anything and anyone with just one hit from our biggest nuke. And saying that the low levels don't matter just doesn't make sense when improving the levelling experience was supposed to be one of Cataclysm's major selling points.