And who said Bull had to bring the Chargers with him? Why not other companions of the Inquisition? It might seem like a test of character, but the Qunari could not have planned for Bull to bring the Chargers and split the groups up as he did. And even if they could, would they really risk a few Qunari and a dreadnaught on one possible Tal-Vashoth, especially when much simpler and less risky tests exist?
Logically, the Venatori have been planning the fire ship for a while and will use it regardless. They already attempted to assassinate at least one of the Ferelden monarchs. So they will keep trying no matter what. It seems the only thing that can even get the Inquisition involved in the first place is the Qunari alliance. Without that, the fire ship should succeed. Even if the Qunari try to stop the ship themselves without the Inquisition, they will not be successful. This is proven by the fact that the Inquisition can also fail if the right choices are not made at the Chore Table.
If you save the Chargers, then the unknown quantity remains an unknown quantity, and is in a position to harm you. Bringing them in close makes you aware of their capabilities and prepares you for them. Also, there are Venatori spies in Skyhold, which again, only the Qunari can pinpoint and trace back to the source.
Well your allies DON'T know that you saved a few mercs rather than got a foothold in with the Qunari. But Ferelden sure knows if you sided with the Qunari and together saved Denerim from being blown half to hell. Pretty sure they're happy about that. And as for what people know about the Qunari, they know one of them helped stop the Fifth Blight. One by the title of Sten, at the time? And King Cousland is friends with him, and knows full well what the Qunari intend to do one day. Ferelden will be ready, thanks in part to the Qunari helping to save Denerim.
Interesting. I can see what you mean. I remember though a conversation about the re-educators that Bull and the Inquisitor had. About changing how someone thinks. Bull went to them before. Predicting someones actions, or helping guide them through social engineering isn't unheard of. I'm still more towards them trying to test Bull, or force him to choose, but I see what you are saying. Though, it wasn't uncommon for groups or governments to sacrifice troops or spies to ensure the loyalty of a higher ranked officer. It happened in Japan, Persia, and many ancient states. Still does in some cases. After all, we only have the word of the Qunari agents as to the conditions of this mission. I doubt even Gatt knows everything.
Also, I admit that this can be chalked up to a writing flub.
True. Assisting the Qunari does give insight, and left alone, they may become a dangerous unknown quantity. That is a very fair point. I don't know if they will fail without the Inquisition helping them...perhaps in that instance, but as nothing further is revealed, its unknown if the Venatori get as far as they do without. Some of it might have been caught by Leliana's people and neutralized before it ever got to the War Table. Unknown. There REALLY should have been something further, consequences and such for picking a side. If THAT had been the case, it would have added depth to your choice, making it harder to just say 'Chargers Forever', and be done.
As to the allies, I'm sure they know, or WILL know. Word travels, and soldiers gossip. The Chargers don't come back, some one WILL talk. They have spies too. Your Orlesian and Free Marcher allies WILL hear of it...it's just a matter of when. Orlais will be shrewd, MIGHT accept it, but the Free Marches would consider it a slight.
AGAIN, there should have been a bigger impact about your choices. The more I think of it, the more it saddens me that this wasn't thought out more. This could have been a big thing. Had a big impact upon the game. Darn it... 