So to put it simply, you are telling me that it would have been more difficult to call for a Landsmeet than to win the civil war? So the civil war was a better /quicker/ safer option? Given the choice, I thought that the nobles would have rather prefered to travel again to Denerim instead of sending their troups to die on a battlefield.
Also, Logain seemed quite eloquent during the Landsmeet in DAO, convincing the bannorn is not an easy task for the warden,every dialogue option must be chosen carefully and depending on Anora's support, the public's favor can be won by Logain.
More or less. What I'm saying is that by the time a Civil War erupted, without a leader for the Bannorn (Eamon or Bryce) in the field, calling a Landsmeet would have been pointless. Old grudges were brought to a head, as Ignacio tells you. The Bannorn are scattered, fighting just as much amongst themselves as they are against Loghain. If a Landsmeet was called (remember, it's an annual thing, and AFAIK there have never been multiple Landsmeets in a year) it would not have done much good because of how the Bannorn was acting.
I must reiterate that the Bannorn are the same people who in antiquity started a war over a tree. Over wool. They start wars over stupid ****.
The only way a Landsmeet would be successful after the war erupted is if there were a few things in play:
1) Anora being able to bring some to the fold.
2) Eamon/Teagan/Bryce (were the latter alive) working to help do that as well
3) The Warden being a capable military commander.
So long as Howe was alive, keeping Anora from doing much in the political sphere, and manipulating Loghain she wasn't able to do as much as she wanted to solve things peaceably. She tried to talk the Bannorn down, but she was in a precarious situation that limited her options, to say nothing of the systemic flaws inherent in Ferelden's government.
This is partially why the Landsmeet we're a part of works so well. We can manage to get all of these things while at the same time finding evidence against Loghain that ends up getting nobles to side against him (usually because it personally involved them). But from a logistical standpoint, we were probably there for a couple weeks in-universe (gameplay makes it seem shorter). And it only goes along so smoothly because of the chaos that has run rampant over the course of the game, allowing us to put a rather quick end to it.
It's more an anomaly then anything else if you ask me, not to be taken as how Landsmeets would typically work.
From a military standpoint, fighting the Banns was perhaps the best thing that could be done, because again... diplomacy once a full-blown war comes into play doesn't work. There's no guarantee that if Loghain had called for another Landsmeet that these rebel Banns would have even gone there. They might have feared for their lives or not trusted him. When Eamon called for it, they had a leader they could look to and were reasonably confident they wouldn't be put in danger.
Is it the safer option? I'd say so, maybe. Consider who Loghain is. He has the greater military under his authority and is the best general in Ferelden. The Bannorn have no leader and their martial might pales in comparison. I'd call it analogous to deterrence, if anything else. By going against them, part of the hope is that they'll not be so stupid to throw away their lives and the lives of valuable men all for the sake of honor in a battle they can't hope to win (indeed, Loghain ends up dominating the Civil War).
Sadly, the Bannorn were a bunch of short-sighted idiots.
Quicker though? Arguable. As I said, perhaps a few months of debate and politics is preferable to war, but I also cannot point out enough that had Loghain called another Landsmeet it wouldn't have worked because vital pieces that ensured success were not in play at that time.
I will say however that some of Loghain's actions only deepened the divide between the nobility and him. How much of this was due to Howe, I can't say.
Under those circumstances, even I'll concede he is likely to have prevailed. (And doomed Ferelden in the process.)
Perhaps, but Teagan would probably have sent an envoy in his place. There was a thing in one of the tabletop RPGs that said that in the absence of being able to make a trip themselves, nobility would sent either family or trusted commoners to vote in their place. Teagan would probably have sent someone (perhaps a knight) and had them mention how Eamon was deathly ill and, depending on when the Landsmeet was called, how it was the result of Jowan -- Loghain's agent -- and how he was in the dungeons of Redcliffe and he could give testimony to that fact.
To say nothing of Berwick.
Which might have just deepened the divide again and pointed to there being no real case to side with Loghain and we're back to square one.
Had Loghain united the bannorn under his command, he almost certainly would have used that vast army to eliminate the (imaginary) threat of the last two Wardens
Hardly. Wasting an entire army on two people who could be anywhere in the world would be an exercise in futility and would only serve to have the Bannorn question him. Loghain, for all his fears on the Wardens, did not send hundreds of soldiers out after the Wardens and it wouldn't be smart to go marching about the country doing that when you told the Bannorn you're going to fight the Darkspawn.
He left only one group of soldiers in Lothering with clear instructions the Warden was to be taken alive, while bounties were put up all across the nation. The people were going to do most of the fighting in that case because of the large amount of gold placed on them.
It's far more prudent to hire assassins to deal with such a thing. Which is, in fact, what Loghain does.