|I'm assuming the achievements highlighted in blue are the account wide ones?|
There has been a freakton of talk about the account wide mounts and achievements. I'm a bit behind the others, but I do have some thoughts on the subject that I thought I'd share. As a confessed altoholic, there are definitely aspects of this that are intriguing to me.
Note: All text in italics are from the official World of Warcraft blog article.
Most achievements are account-wide
This means you only earn the points once. If you have earned an achievement on one character, you can see it on all your characters. However, and this is important, you will still see the achievement toast (the pop-up notification) if a second or subsequent character completes the achievement. We think it’s still important to recognize milestones like reaching level 80, maxing out a profession, or killing a raid boss for the first time. It's fun to have everyone congratulate you when you get the toast. Nonetheless, this will just be a new character of yours completing the achievement that you’ve already earned on your account. You won’t double up on points.
I get that they don't want you to earn the points twice and I like that you'll still get the acknowledgement for completing achievements on all characters. However, it seems redundant to be earning the same achievements on all characters when they've already been done on your account. Personally for me, I'll feel a lot less inclined to try and earn achievements on more than one toon when I know that it really doesn't count. And I mean the achievements like "To All the Squirrels I've Loved" and "Pest Control" (two of my favorites). Meh.
Most criteria are not account-wide
If you start an achievement on one character, you can't then finish the achievement on another (there are exceptions, so please keep reading). We didn't think it made sense for one character to get level 60 and another to get level 20 and then see the "level 80" achievement toast. If you start to explore Thousand Needles on one character, you’ll probably want to finish that achievement on the same character.
This actually makes total sense.
Some achievements are "meta achievements."
These are achievements that require you to get other specific achievements. An infamous example is "What a Long, Strange Trip It's Been." These achievements generally ARE account-wide. If one character earned Noble Gardener and another character earned The Flame Warden, then your account would get Long Strange Trip. (Otherwise it would be weird: it would look as if you had the sub-achievements, but you wouldn't have the meta-achievement). Even though you need Explore Thousand Needles on one character, all of your characters can contribute to Explore Kalimdor.
Ok. This one is logical too. It would make getting the exploring achievements, for one, way easier.
A few achievements are account-only.
There are two categories of account-only achievements. One is achievements that are not possible to earn on one character. If we made an achievement to level every class to level 90, it would be account-only. (I'm not sure we will, but it's a good example.) The other category are achievements that are just brutal to complete on one character (and you’d never want to do for multiples), such as 2500 daily quests or 250K honorable kills. In these cases, the cumulative work of all your characters on those criteria will count.
It took me a second to get this one. I like the idea of account-only achievements, especially the one they give as an example. It's nice incentive. "Cumulative" work is also nice but it makes getting those types of achievements easy.
We hope that rewards granted from achievements (pets, mounts, titles, and tabards) will be shared at the account level.
I'm not going to promise this yet, because a lot of magic has to happen for that to work, but it's our intent. We have discussed having a character level requirement for some rewards, so that your level-2 gnome couldn’t walk around with the “Defender of a Shattered World” title just because your level-90 shaman earned it. If the gnome made it to level 80, though, you could proudly show off your title. You also won’t be able to use a faction-specific pet, mount, or title on the wrong faction. The achievement wouldn’t go away -- you just wouldn’t be able to show it off on that character. There are probably additional exceptions and details we’ll find as we dig deeper into the system.
This is where they start to lose me. Earning these types of rewards should be earning these types of rewards. Making certain achievements have level requirements would be an absolute must in order for me to not completely hate this idea.
What gets me about account wide achievements and mounts is that this is just yet another way that Blizzard is "dumbing down" WoW. They make everything so easy to get nowadays, that the feeling of having worked at something and completing it isn't there so much for me anymore. I also think that players should have to "pay their dues" for certain things. If they keep lowering the level for when we can get our flying training, they may as well just increase walk speed. You know what I'm saying?
Making achievements, training, leveling, dungeons, and raids too easy takes away that sense of accomplishment. I don't want to play a game that a two year old or someone's pet monkey could master.