The Hero of Ages question

I enjoyed most of the the first two books of this saga almost as much as I enjoyed the first three books of The Stormlight Archive. However, a couple of major flaws in the saga are severely spoiling my enjoyment to the point I do not think it is worth reading further. I will explain myself.

There are two events in the first two books that are so absurd, so illogical, so stupid and so forcefully inserted into the plot for no good reason, or without spending a little bit of effort to provide a plausible explanation for them, that the whole plot of the series seems pointless. I feel that if Sanderson wants to reach some specific end of this story without taking the time to develop it properly, he could just tell us how it ends and avoid us the time and effort to go through a pretense of a plot. And that makes me angry, not only for having spent a significant amount of time reading the books, but also because he is a writer I generally enjoy and who is capable of very good stuff. And it also surprises me quite a bit that other readers did not seem to notice or care about this. 

[Spoiler warning] The first of the events I am talking about is related to the secret skaa army being destroyed and wasted for absolutely no reason. It is not an issue of overconfidence or miscalculation of the strength of the army or its opposing forces, but that there is absolutely no point in testing an army that is supposed to be secret before it is the right time to use it. And it cannot be explained by a general being stupid or going mad. Many thousands of soldiers would need to agree to this madness that not only will result in their almost certain death, but it will defeat the goal for which they have trained so intensely and risked so much, including the future of their families and the skaa as a whole. Utter nonsense!

The second event is the fight between Sazed and Marsh. Sazed, after having narrowly avoided being killed by Marsh and luckily being able to momentarily incapacitate him, who is known to quickly regenerate (as all steel inquisitors do), instead of finishing him, he just turns his back on him and leaves. That is not only stupid and suicidal, but knowing that Marsh wants to kill his friends, letting him go is nothing short of becoming an accessory to murder. It is difficult to conceive an event more absurd than this in the plot. I will not be able to read through the other books without thinking at each Marsh future appearance that this character could not really be there.

One big flaw may be dismissed, two do show a clear pattern. My question is, do the other books provide a valid explanation to these senseless events? Or, if they do not, are these just a couple of unexplainable very unfortunate mishaps in Sanderson's writing that do not repeat themselves, or are there other similarly absurd events in the plot that would make reading the rest of the books a complete waste of my time?

Thanks in advance.