Blade and marksman?
It's usually best to go with one or the other. Switching between combat is hard.
Magic is a good combination with anything however, as you can cast it no matter what your wielding.
Problem with marksman is that it require a lot of use to become a good skill, so you either use bow as primary weapon or simply a way to poison somebody from a distance.
if you are an archer you would want a fallback weapon mostly if the enemy get to close.
Archers also has less use for armor as they do ranged combat.
And magic is always useful.