Is Alexander supposed to be strong or not?

[Ghieri]

In the end, I think Alexander was easy to defeat because he grossly underestimated Daniel.

Possibly. The added stress of the shadow closing in and focusing on a ritual didn't help either. I think that:

-Alexander relied almost completely on the barrier to protect him.
-He forgot about the other orb.

At least, that is what is implied by Agrippa.