Olwen starts with 10 speed. That means she has 0 AS. Any enemy with 4 speed will double, and probably kill her.
Her growth in speed (50) is nice, but will take several level up to get to at least having and AS at all.
Thorons have short usage (10) and you do not get as many of them in Olwen's route. On the contrary; you get a bucketload of them on Eyrios' route.
Exactly, so the Daim thunder "advantage" is gone.
Scroll abusing (although practacally everyone does it, including me) cannot count in favour to Olwen because I could do the same with Eyrios.
Holy sword is a nice weapon, but eyrios has a A in swords, so he can use sleep, master, hero (even better), silver, and kill swords as soon as you get him.
I consider it better to have use of any non-prf weapon for the whole game then to have holy sword from chapter 22 onwards.
You do not have to worry about weapon ranks with Eyrios. Swords are very useful; use a sleep sword to dismount enemy units to capture or steal from, use a master (or better a hero sword) to finish enemy before counter, use kill sword for awesome critical, use silver for power, and so on. It counts alot.