Wouldn't making archer's abilities not require charging kinda defy the point of archers as a class?
Like seriously, the skills are quite good with the charging and come on, archers do need to draw their bows in real life
I do believe that archers should receive a buff on the arrow damage, say x2 or x3 as the main weakness of archers is their low damage, not inability to spam shoot 20 arrows per second. Note that increasing the arrow damage will at the same time make all archer skills more effective, thus solving the skills problem.
I do however recommend that the skill piercing shot should be changed to either have unlimited piercing amount or being able to upgrade to like 10 enemies at once as archers don't really have a splash skill that can clear a room of monsters, unlike say cowboy's grenade and the piercing shot should actually be able to actually pierce through everything anyway.
Definitely, support damage buff (archers need a big one as can be evidently portrayed through the lack in the number of archers) and perhaps consider redesigning the piercing shot skill, but I don't think archers need to be able to spam 20 arrows per second like cowboys.