On Earth, women are not suitable for medieval combat because they are physically weaker.
On Nirn, women are equally strong as men. Don't believe me? Just look at the stats! Obviously females in Tamriel have a higher muscle density than males since they are smaller but just as strong and fast.
Been pondering this here "physically weaker" part...
Here's the thing: Women might be physically weaker than men,
on average. But if you still decide to, say, grab a sword, and go do some fighting, doesn't it make you MORE heroic? You're taking and overcoming much greater risks than someone who's been born with inherent size- and strength-advantage. Heroism is all about overcoming your disadvantages, and doing the right thing regardless of circumstances, after all.
People who are born exceptional and keep becoming even more exceptional make for boring characters. The most interesting characters in stories tend to be those who have the odds stacked against them, but still manage to win.