They were the only international organization in Thedas with enough men to keep several Circles meant to contain living cannons.
I'd say that, the simple fact they're international means that, should they pool their numbers together, they should overwhelm any national military, especially when the Orlesian one is divided.
Plus, they are all specially trained soldiers while national armies vary from Chevaliers to peasants armed with forks.
Being trained to deal with mages doesn't mean being able to deal with normal soldiers. Of course, just being trained at all is a plus for them.
But are you sure with the numbers? Yes, being an international organization with several garrisons is good, but remember that the Circles aren't the only keeps in the world. Thedosian countries are, in general, feudal societies. Each feudal lord should have at least a keep, and each keep a garrison. Then add the royal army to that and the levies, and that would make any national army far greater than the combined Templar forces, at least in numbers.
I think it's not a coincidence that the game is going to showcase the Mage-Templar War in Orlais and Ferelden. The first country is in the middle of a civil war and the second country is recovering from another civil war and the Blight. I don't see the so far intact Nevarran forces allowing any kind of bullshit from them.
I'm guessing we'll be less pro-Templar or pro-mage and more pro-peace, pro-common people, pro-lets end this bullshit war right now.
Which suits me just fine; unsuprisingly, it's not the "opressed" mages who are suffering the most from this, it's the little man.
Yeah, I agree. Those who suffer are always the same.
To the mages: "Oppressed? Oppressed?! Take a look at those peasants! They are oppressed, for real! Oppresed by their feudal lords, by taxes, by criminals, by famine, by sickness, by climate itself! And now you think that it's funny to throw fireballs at them because they didn't like you and didn't give you what you wanted? So you should have life and freedom, but those poor souls not?"
To the templars: "And you! You! So, "champions of the people, protecting the world from the dangers of magic"? And who protects the world from you? The moment you realized that you didn't have money or food, you started robbing the very people you ought to protect! And then you had the nerve to kill those who complained and accuse them of being mages or aiding them!"