I can't finish the game as anyone but a Mage.

Like being an apostate in a city full of Templars casting spells in public. 

Apostates exist absolutely imaginable. I love that mage Hawke's an outlaw, even if s/he's a noble. An apostate doesn't have a home. As a warrior/rogue, we can experience that, only if Hawke worries about Bethany in danger in the Circle, and wants to free her, no matter the cost, but if not – then Hawke just a noble, who helps people and shit happen around him.

As a fantastic feeling to walk in the Hightown openly – knowing, that I can lose that in a moment, and become pariah again. As warrior/rogue this feeling again: just if Hawke wants to free Bethany or worries about Anders/Merrill, and able to leave everything that s/he earned, for them. The mage able to leave everything for his/her people.

I love Bethany – I love she's a revolutionary at the end, but I don't like so much the martyr. She' s much better than that boring good girl at first sight, but many people love her only because she's not "problematic", she just loves Hawke, whatever Hawke do, even if kill her.
So easy to betray her – she will accept that, without a word. People love if the others around them are obedient, or just don't show their opposite opinions. In fact much better if they do not show any opinions.

But Carver is great. A true second son. His brotherly rivalry and/or a slowly formed friendship is great.

___

As a mage would be more interesting the opposite view too: I betray my people, I betray what I'm because I think, I'm able to cross my shadow.

True enough. That said my canon Hawke (Ionie) is a Mage and I can't see Hawke any other way. 

Mage makes for a much better story, but Rogue has always been my preferred class, and how I completed most playthroughs.

I've completed the game as all three classes a while ago (I haven't done sword and board and archer). To me, mage Hawke makes the least sense to me but mage is at least fun.

I actually plan to replay this game as a female Hawke and make her a sword and board warrior so I don't have to take Aveline with me.

I've yet to finish the game as a warrior
most of my Hawke's are mages...the female ones anyway
my male Hawke's tend to be rogues
don't ask me why, but I just like them that way

the story doesn't make much sense as a mage, but you have to remember that it's Varric who's telling the story to Cassandra
so hell no he'd tell her about every occasion where he had to cover for a mage Hawke because someone saw them casting spells
plus, it's one of the reasons he invites them along on the Deep Roads expedition, either to protect Hawke...or Bethany
Varric: look, I know the Templars have been asking questions, how bad would it be to get out of the city for a while?

I mean, in (party) dialogue he says that he's protecting both Merrill and Anders by having the authorities and goons turn a blind eye
Varric: Daisy, for my sake, please quit cutting through the alleys in Lowtown alone at night.
Merrill: Nothing ever happens. I'm perfectly safe, Varric.
Varric: Yes, I know. And that nothing is costing me a fortune.

Varric to some random guy at the Hanged Man: let me know if you hear any more rumbling from the Coterie about protection, Blondie has enough trouble as it is

and let's not forget the conversation you have with Tallis during her introduction in MotA
Hawke: what makes you think I steal things because people ask me to?
Varric: I ah...may have talked you up a bit...maybe more than once
Hawke: *sighs* oh Varric
Varric: what? You'd rather I tell everyone you were a mage?

So yeah, the story doesn't make much sense as a mage, but it's enjoyable nevertheless

I solve that by not letting Hawke fight whenever there are npcs nearby. The other companions do all the work.

And I certainly do not choose the dialogue option where Hawke reveals to Vincento that he is a mage. 

That's funny, I have it the other way around. Finished once with a dagger rogue, once with a sword'n board warrior, and lost interest in the first half of chapter 1 half a dozen times with mages. And now I'm cruising through the game as a bow rogue, and having a blast.

Don't know what it is. A few of the spells are cooler-looking (Cone of Cold is all I want to do all day, though it should probably be renamed Spray of Cold), but most are just lazy and it really stretches my suspension of disbelief for Hawke to be a mage and not arrested within the first hour of the game. And frankly, I just can't stand Carver's attitude. If he was my brother, I'd have beaten the crap out if him to teach him a lesson long ago, just to see if it would stick when nothing else seemed to.

I don't see the point of the "Mage Hawke feels more central to the Mage/Templar storyline" argument. S/he isn't. At all. Anders carries that just fine all on his own. Hawke is just... there... when things tend to go down. In my head, Hawke works better as a classic working-class adventurer and glory hound, seeking his/her fortune and getting caught up in events way out of his/her league for mercenary reasons, and because s/he has a lot of unfortunate friends and family, and feels compelled to protect them. Warrior and Rogue both work better for those themes than Mage.

I also find the fortune-hunting angle a lot more relatable than fighting for freedom. Before television and movies suddenly convinced us that we all had happiness and glory waiting for us eventually, it was considered every man's responsibility to fight tooth and nail to improve himself, his lot in life and that of those who depended on him. Building and protecting your reputation, making connections and trying your damndest to move up in the world was what life used to be about everywhere. Hawke's story echoes that. In comparison, the "Freedom for Mages!" conflict is pretty hollow, and doesn't do the Templar's side of the debate justice at all. That works better as Anders' pet project/ill-considered crusade which blows up in everybody's face, rather than something Hawke is supposed to have an intrinsic stake in from the get-go beyond protecting his/her sister.

The fact that Warriors and Rogues were at Ostagar with Carver appeals to me as well. It's a fairly strong common thread between him/her and the Warden, as well as Loghain if he's still alive and working with Hawke in Inquisition. A rogue Hawke completes the trifecta of Rogue/Warrior/Mage between all the siblings too. And it also helps sell the feeling of each child having a different role in the family. Carver is the hardworking but whiny brat, Bethany is the favored and sheltered - but also better educated - middle child, and Hawke is the more experienced and decisive older brother/sister who stepped up when daddy died because mom was kind of useless. Having Hawke be a mage steals a bit of Bethany's spotlight as their father's heir and special little girl.

Also, the kickass Hawke Sisters rule forevah!!

Here is the thing, though. Mage Hawke struggles with everything you mentioned and can have the same desires as a mercenary.

The only difference is that it is all that, plus the mage freedom issue.

The connection with Ostagar is exclusive to rogue/warrior Hawke, though.

Noxluxe

One question: who wants to be "normal" in Kirkwall? Embrace the madness, and everything gains sense!