Well considering that Gaidar has a really bad habit of outright retconning stuff in random interviews what is actually shown in game is far more important then whatever his opinion might be on any given day. (Alistair, Hawke, and the Warden all prove that Templar's DO NOT get their abilities from consuming lyruim ... Alistair's parentage being changed for no apparent reason, ect...)
However, let's take a look at what actually appears in game;
-- Loghain couldn't see the battle from his advantage point, which is why he needed the signal fire, and Loghain did know that said signal was late. ... It does make some sense that he would realize that something went seriously wrong.
-- We know that Loghain ordered Eamon's poisoning before the battle, and as far as I know, the ONLY person who claims that Loghain didn't "really" want to kill Eamon is Gaidar, nothing at all in game ever hints at suggesting this. Not to mention that Gaidar's "explaination" of why Loghain poisoned Eamon is loonytunes at best and not even hinted at in game as far as I'm aware.
-- We know that Loghain is always portrayed as loving his country above all else, with his daughter a close second.
-- Loghain didn't seem to know that the Child King was really going to divorce his daughter, although I do believe that it's hinted that he did "suspect".
-- Howe on the other hand, is an evil bastard by all accounts, and he did suddenly seem to be "besties" with Loghain.
-- Had something NOT happened to the Child King then even Howe had to realize that killing the Coustlands was suicidal. -- You simply can't keep that a secret as many men as had to be involved, without Howe killing all of the men involved, which while in character with Howe, isn't mentioned as far as I'm aware.
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Now, with that said, I don't blame Loghain for withdrawing from Ostagar, that battle was already lost and had he charged then his men would have been lost as well. However, you do have to take a serious look at how convenient the massive defeat at Ostagar was for Howe and question "how" Howe thought he was going to be able to get away with it had Ostagar not gone the way it had.