i. Tevinter Imperium have war with Qunari for so long, they know Qunari have gun powder, why those Mages never steal this thing and used it against Templars?
ii. With a gun, there is no need to waste years learning magic to become powerful just because want to compete with Templar anti-magic power
iii. No need to deal with demons for Blood Magic, the reason to use blood instead of mana is because want to against Templar who can drain mana and nulify magic
iv. Qunari will sure conquering the world because nothing can stop gun unless someone in Thedas is Neo who can stop bullet in mid air
v. Anders know how to make bomb, powerful bomb it is, so it is just logic Mages know how to make one themselves, why they never make it to against the one who opress them all these time?
vi. All the Mage vs Templar conflict can just simply solved with gun
Didn't read through all 14 pages of this topic, so forgive me if I'm just regurgitating someone else's previous comment. Here is my take on these points..
I. Qunari generally stay isolated, so it would be difficult for a rogue mage or extremist mage sympathizers to get a hold of this without getting killed.
II. In the current DA universe, the only people that have "guns" are those guys in the Descent DLC(which was probably just rapid fire crossbow bolts). Obviously this tech was developed exclusively within their civilization and has not been developed/discovered by anyone else. Also, you're born with magic powers, they just go to school to learn to harness and control it... which only makes sense, even if you weren't harnessing it for war.
III. If you're a blood mage, why not summon demons to help you in battle? Or use any other typical blood mage ability?
IV. Qunari haven't developed firearms at this point. They essentially just had developed a compound mixture that was a highly potent explosive. And even if/when they did develop firearms, it would likely transpire like actual history did. There would probably be a one sided war in an area, and the rest of the world would eventually catch up to their technology. Even in real life though, this process of from making explosive "gun powder" to actually implementing them into firearms took a LONG time... and the first firearms were pretty rough to the point that skilled bowmen/magic projectiles would be much preferable to someone with a gun.
V. Because not everyone is so violent that they are willing to commit mass murder. Take the current real world for example... You don't exactly need to be an explosives specialist to make a bomb (IE: Boston Bomber / OKC bombing). Those guys involved weren't scientists... What makes the difference is that you have to be willing to kill a large number of people willingly. Even people who are historically oppressed end up just accepting how things are and just rolling with it. It takes a real extremist to do something like bomb a building and kill countless people.
VI. Well since neither side has guns, I don't see the argument. I assume at this point(post-DA:I), the Mage/Templar conflict is over for the most part. But if you're talking about future conflicts, what's to stop magic users from implementing their magic into guns? See my previous post.