Is hermaeus More more powerful now that he has the Secrets of The Skaal.
sorry if this is in the wrong section.

Being the daedric prince of fate and knowledge any sort of information would make him slightly more powerful (just look at the huge variety of books he has in his realm), but information in skyrim that is heavily guarded (such as the dwarves as well as the skall) would increase his potency. The knowledge itself may be extremely powerful, or is as such because of the sentimental and cultural value it has to the people who guard it. Maybe both. How "great" a piece of knowledge is obviously is quite subjective.

It depends on what the Secrets of the Skaal actually are, wouldn't it?

it may be some huge, world changing knowledge, or it may be a new way to cook Salmon....

mmmm..... Salmon....

My impression is that the reason Mora wanted the secrets of the Skaal isn't because it was some earth-changing knowledge, but because it was something he didn't have. Mora stockpiles knowledge, regardless of it's usefulness, and the secrets of the Skaal was something he didn't have. Whether it was anything of import or not is irrelevant; the only reason he wanted it is because he didn't have it.

That, at least, is the impression I got.

In the sense that knowledge is power I suppose so. As far as true power most likely not as Herma Mora retains his original nature. That would be my guess at least.

It's not like he can practically use it. He just wants it.