Zu Long wrote...
1. Your counterpoint here doesn't address the point in my post. If anything, it reinforces it. With, as you put it, incomplete information about the actual size of the Darkspawn army, and as I said, NO WAY to see the battlefield, it would seem to give lie to the idea that Loghain only left because of how badly outnumbered they were. It wasn't a tactical decision. It couldn't have been, based on what we know. It was purely a political betrayal of Cailan and the Wardens.
WHAT WE KNOW is that our Wardens and Alistair were supposed to light the Beacon that gave Loghain the signal to join the battle, WE obviously failed to do so in a timely manner considering the Tower of Ishal was inconveniently overrun with Darkspawn. We also know the King Cailin and the frontlines were getting smashed as soon as the battle started, had Lohgain joined the battle after our LATE signal we likely woukd have lost Ferelden because there would be no Army left, purely tactical decision, although it doesn't help he found out Cailain was planning to become an Orlesian Emperor.
. On the contrary, we know that Cailan was in favor of allowing the Orlesian's to arrive and help. If Cailan was dead set on winning the battle himself and having songs sung about him, why invite the Orlesians at all? If Cailan truely suspected the Fereldin army couldn't win, as we've been told RtO, then it stands to reason that he placed himself in harms way at Ostagar so that Loghain would have to see the futility of going it alone. Cailan probably suspected Loghain would leave the Grey Wardens to die and insisted on being in the blocking force so that Loghain would be forced to come get him. (I realize there's quite a bit of conjecture in there, but it's the only way the pieces we have from Return to Ostagar make sense.)
So your saying Cailan joined the frontlines so Lohgain could save him and the Wardens?

3. The archdemon hadn't been spotted, but the experts on the subject, ie the Grey Wardens, were certain that it was and told the King and Loghain so. Disbelieving them, as Loghain seems to have, is simply more indication of how poor his judgement had become. Consider that even the Wardens all the way in ORLAIS thought it was a Blight, according to the letter from Empress Celine.
I assume you haven't read The Calling, otherwise you woukd know the only previous experience Lohgain had with Wardens was when they Dragged Maric on a suicide mission and He ended up watching the Architect turn 2 of them the Ghouls and Tell his plan to Taint the World, oh yeah Maric almost because of that too, so Forgive Lohgain for not being trustworthy.
Those who don't learn from history are doomed to repeat it. Again, Blights had happened FOUR times in the history of Thedas, and Loghain really had no reason to disbelieve the Grey Wardens except that he found it inconvenient. Grey Wardens had been required to slay end a Blight all four other times, so he doesn't really have an excuse for believing this time would be different. Claiming that "other Wardens" elsewhere exist sort of glosses over that Loghain IMPRISONED AND TORTURED the first Orlesian Warden who crossed the border to find out what was going on. By the time any of the other Wardens got a crack at the Archdemon, it's pretty clear that Ferelden would have been toast.
Your operating under the assumption that General Population is aware Wardens are tainted, because they are not. The fact the The Taint inside a Warden is the only thing that kills a Archdemon IS A SECRET. Lohgain probably thought a common army could defeat the Horde, which was not known to be a blight at the time.
Loghain allowed his fears and hatred of a past enemy to overwhelm everything else, and put everything he had sworn to protect in danger of total destruction. Tactically, he made two terrible choices leading up to the battle (disregarding the Warden's warnings of the size of the threat, and refusing aid from another power) and another terrible choice in abandoning the battle when the only force that could save him was facing annihilation.
Actually he made very sound decisions, He would have failed because he didnt know he needed Wardens. BUT THAT'S IRRELEVANT. The Orlesian/Fereldan war only ended about 30 year's before the 5th Blight, so Orlesians arent exactly a "past enemy". Ferelden is literally 5 years into its second Fereldan King after a 100+ year Orlesian Occupation when Origins begins.