To bud into Crongkong's and Paramitch's conversation: In Origins, some banner with Sten and Alistair when Al becomes King asks if it's possible to end up in negotiations with the Qunari which Sten bluntly says 'no, we don't negotiate'. Convo taken from DAwiki:
Alistair: So I suppose once I'm actually king I could end up in negotiations with the Qunari one day.
Sten: My people do not negotiate.
Alistair: What do you mean? They negotiated a peace treaty after the war, and as far as I know they've kept to its terms.
Sten: They signed a piece of paper. But only because they knew that you believed in it.
Alistair: And what is the difference between that and negotiating?
Sten: They stopped fighting for their own reasons. And they will resume it again, one day. The agreement means nothing to them.
Alistair: But I thought you said your people believed in honor.
Sten: They do. The honor of the Qunari is what will bring our warships back to your shores.
And Alliance involves negotiation on both sides to find common ground and to the Qunari, there isn't any because to them; you are all Bas (things) that need to be taught and and when Allister asked about honor; honoring to them means 'teaching' all of Thedas to live by the Qun.
The whole Dreadnought thing was one sided being they didn't even try to find common ground or think of a plan with the Inquisition regarding that mission to begin with that worked with them or could have been even better. They thought they were right and only they were right and shot down any ideas the Inquisitor even suggested. Even Gatt straight out says that the Qunari don't bargain. That in itself should raise a Red Flag that this Alliance wasn't going to work out.
And they lost people for it if the Inquisitor tells Bull to call the retreat, and being this was mostly a Ben Hassrath mission; they respectfully screwed up big time for having their ship THAT CLOSE to shore to begin with so they couldn't at least get out of range. Yeah, Dreadnoughts are slow; but if positioned right they could have possibly had a higher chance to get out of there suppose to being right beside the beach and letting their ship get blowed up.
I rather have a small merc team that I know is loyal suppose to an huge alliance which is shaky at best and even called out that the DotQ mission was going to bite the player in the ass far before Trespasser was even announced.
(That and I personally can't do that to Bull. I love him too much to let him go though that pain again after the crap he dealt with in Serhon).