I think we need to define "Mature" in terms of RPGs, and fantasy settings, don't we?
It's going to be impossible, too, because "Mature" has come to mean a lot of different things, from "There is a lot of blood", to "There is a lot of nudity", to "There is a lot of violence" and even "There are uses of alcohol".
I would say it "Mature x"("X" being a movie, a book, a game, or something else entirely) would, or perhaps rather "should", mean that this work ("x") is targeted at a "Mature"(I.e. older) audience. It deals with adult themes.
Now, we can add several other words and descriptions to "Mature", but I do not think anyone (or anything) can look "Mature".
You don't "Look" mature. You "Act" mature.
So in a sense, you should erase that word from your post altogether. "Cool" is an, to me, entirely undefinable word. What is "Cool"? I have different definitions than you, and I'm not going to find everything "Cool" that you find "Cool".
Now, if you're asking me if the animations look over-the-top and void of realism I'm going to agree. I realised during the first pieces of information revealed about DA2, however, that that wasn't where I would get my biggest kick, in terms of animations or sense of "realism".
I certainly do not like the direction taken by Bioware here. Not in the slightest bit - but I can understand why they're doing it. I'm sure there's a bigger market for over-the-top kind of animations and characters, than those who look stiff and unreal in their own pathetic way... I would just have wished for some sort of middle ground.
And do not confuse yourself, the game is certainly only aimed at a "mature" audience in terms of story and surroundings, while the animations are catering to the crowd of "youngins", just like the whole of their marketing campaign is. Apparently, that is where the money is.
This isn't going to look like a video-game version of the A Song of Ice and Fire books, but did we really expect that to be the case? If only Bioware had shown some kind of restraint, and not gone so (to me) excessively over-the-top that it looks ridiculous and stupid.
I only hope the content of the game itself will allow the player to interact with more "mature elements" than DA:O, as I felt most of the world around the player was interesting and would have been awesome to explore in the form of side-quests or being integrated into the plot. Basically, I'm hoping for less "High Fantasy", and for a more dark story - that is neither here nor there, though, as this threads deals with the animations.
In short: I agree with you, that the animations look stupid. They aren't "Cool", however (to me), and they are by no strecth "Mature" - given that that would make little sense.
To add to that, I don't think Dragon Age 2 is "trying too hard" to appeal aesthetically to youngins, I think it's doing exactly what it set out to do. Hell, you knew where all this was going from the minute "Fight like a ninja, command like a spartan", or was it just "Rogues are more like ninjas" "Turn-based chess-like games are boring", and "Fight like a spartan, command like a general"? where it was all going.
I just hope, as stated, that the story offers me more than DA:O, hell - I would really like to see some kind of interesting twist to the storyline, or any kind of awesome storyline at all. While the writing has been awesome in every Bioware game I can remember - the story and plot has certainly not. There was nothing interesting about the overarching storyline in DA:O. At least not to me.
Again, in short:
Dragon Age 2 is achieving exactly what it set out to achieve. Have people like you complain - that, most likely, means they hit the nail on the head when they wanted to cater to the "Likes over-the-top animations" kind of crowd.