Magic Arrow 10 is a 25 hit skill on a 5s cd.
Its probably the most powerful single skill in the game if you’re fighting a boss that will sit in each Magic Arrow for all 25 hits.
Magic Arrow 5 is only 15 hits, but if you take into account that a lot of bosses move around and won’t sit in Magic Arrow for all the hits, then Fletcher 2/Musketeer becomes competitive with Fletcher 3.
Against bosses that can be made to sit in one spot and eat each full Magic Arrow, Fletcher 3 is insane though.
I’d suggest Fletcher 3 over Fletcher 2/Musketeer if you want to save silver on upgrading the Musketeer skill attributes. But having a more diverse skill set and complex rotation can be more engaging.