I think the disparity of agreement here is coming from a basis of how people roleplayed (or perceived) the way the game played out. Andy seems to like playing badasses who singlehandedly get the job done, and while one can argue that their PC was a total badass, wiping the ground/floor with their opponents and an obvious candidate for recruitment, it can also be roleplayed that the PC has other qualities that would recommend them. Or even that circumstance alone (an element of luck as it were) plays into the situation as well. Even that they don't want to go at all. As I already said, there is no 'right' or 'wrong' way to play as long as what you are playing is fun.
Well that makes me sound immature... 
My CE was clever, quick on her feet, but not a combat machine.
My Dalish protested every step of the way to Tamlen initially and then Duncan's recruitment (and I imagined Duncan having to actually cart her off bodily to Ostagar).
My DN I already explained upthread.
My mage actually assisted Jowan, finding the circle's rules too oppressive and Jowan's fate particularly cruel. And the fact that Duncan seems more impressed with this than that you were doing it for Irving had a little to do with it too.
My DC was a scrappy little thing, but I drugged the other opponents. No way would she not take advantage of that. And the carta...well that was all about killing them before they killed her (and protecting Rica from Baraht). But once she saw Rica was going to be okay, she jumped at the chance to go with Duncan.
My CE is both. She fights with wits and stuff, but she's also very good at full-on combat. I imagine her being a dodging-machine, can somehow be completely surrounded yet practically unhittable. Around mid-game, that's actually what she ends up like in gameplay. She's fast enough to literally hit arrows out of the air or dodge them easily by just moving her whole body in a very flexible way. She's practically like liquid in combat, dodging in ways that would make an acrobat green with envy. She makes use of being very small framed. My Dalish is the same way actually, both my elves fight like this in my mind. She didn't want to be a warden, but it was a better option then... Ugh... An arranged marriage
. My Dalish didn't want to become one either, but they knew that it was either become one or die. Who wants to die?
DN, I also already explained. Fighting style, dual wield warrior. Not much dodging at all like my elves, their style is using 2 longswords at once (rogues only use one sword or 2 daggers) and using a lot of power. I imagine them as being more focused on blocking them on dodging, using the gigantic wrist plates of the heavy and massive human gauntlets to block and deflect attacks and then follow up with counters. They max out the middle dual wield tree which my rogues always ignore, which helps play into the "more power and defense driven" style compared to my dual wield rogues. This fighting style is also my HN's warrior style (dual wield again, it's the only weapon type I can stand in DAO). So while the elves are dodging every which way, my warriors just stand firm and just tank and block and counter every attack thrown at them. Warriors are power and rogues are speed, and my headcanon of how they fight reflects that.
My mage... Changed on the playthrough. Sometimes I help Jowan, sometimes I tell on him and am happy to help him get caught, and sometimes I tell on him but try really hard to wiggle out of what I was ordered to do to get him caught.
DC is always rogue, as I said earlier. They're kind of a mix of my warrior and rogue-elf styles. Them being thicker and more stout and much wider than elves means they can't just dodge everything thrown at them, but not being a warrior means they can't just tank everything either. So they do a bit of both. They do more simple but effective dodging with a mix of some blocking. They can't dodge as well as an elf, but being a dwarf does mean they have more strength to work with and more thickness of arms and arm length to brace themselves which means they can certainly block a hit easier than the elves. However, they block with their daggers unlike my warriors who block with their gauntlets. So they're not as good at dodging as the elves, and not as good at blocking as the warriors thanks to needing to do it with small weapons, but can do better at both dodging and blocking than the other 2 can. I said warriors are power and rogues are speed, well my DC more or less goes 50-50 between both those traits. Simple biology means they can't dodge like a skinny and lithe elf can, but their thicker build also gives them advantages the elves don't have. I imagine them as doing simple backsteps and sidesteps and small body position changes to dodge as opposed to the backflips and somersaults and flips and other crazy stuff my elven rogues do for dodging, mixed with some well timed blocks with their daggers.
Does that sound way too badass to be believable?
The situation is not comparable. If anything, Cousland and Tabris switch roles in their Origins.
In Denerim, the Arl would have taken all the best men with him to Ostagar making the ones the CE fights the greenhorns who should have been perfectly capable of controlling a civillian population. In Highever, Howe's whole army is there, elite troops included, there are even apostate mages there.
In Denerim, the CE is the one catching the guards by surprise. In Highever, the Cousland are the ones caught by surprise.
So, in both cases Tabris, circunstances give Tabris an advantage while taking it away from Cousland.
That is not to say what the CE did wasn't impressive. Hell, if I'm being honest, it's more impressive than what HN did. But circunstances do aid and hinder fighters tremendously.
After all, if we just say that the CE can slaugther 27 soldiers nearly by himself/herself, there are fewer than those escorting Vaughan to the wedding and more elves around to help.
Go for it!
Except if you are the son of the king. Did the DN origin really give you the impression this was a story about an exceptionally skilled young man who rose through the ranks and became a general/commander before he was even 30 years old? Or that of the spare son/duaghter of the king being given a ceremonial position because, not being the obvious heir, it was expected to still be in an elevated position
That is not to say the DN hasn't experience leading men and fighting against Darkspawn but the impression i got from that Origin is that he or she is being given command mostly due to having "Aeducan" as a last name.
Well, good point, you DO catch the guards by surprise. Especially just by being an elf. (tunes into Mordin's way of thinking for a second) Humans, dwarves, qunari, all obvious threats... *sucks in air* Never see an elf coming. And yeah, the REALLY GOOD guards were probably taken to Ostagar. I'm not changing my score though, they still deserve a high one.
I do in fact like to think the DN earned their rank instead of it just being given to them as a freebie. Dwarven society can't afford to put their most promising and untested soldiers against darkspawn without being ABSOLUTELY SURE they're ready for it.