we are talking here about BOWS not a single archer would think about trying to hit someone or something with his bow. he either payed alot for this piece of master work or he did it himself and knows how fragile it is. if you want to use a bow to hit somebody: hit him once (doing no damage unless to naked people) and find your bow either broken or just atleast unusable.
have you ever held a longbow in your hands? they have to resist up to 130 pounds draw weight (!) so you could stand on one of them and it won't break. (I am speaking about the big warbows now, not any composite bows for horse archery). Of course it does not that much damage but in general there is not much difference to a normal wooden stick which is already in use in crpg. And if you talk about the string, well, it is not unusal that a string broke when you where in battle. they were objects of utility and nothing really precious. (warbows often had strings out of linen and not tendons) Thats why archers always kept some dry strings between their head and the helmet, when they were lucky enough to have one
so talking about the realistic factor at least for the 2 slot bows it's not that impossible. after all, the archer is fighting for his life when using this. he wouldn't take care of his bow.
but as others have mentioned this could be a problem with archers who could fire another arrow before having to pull out any melee weapon to block.
so difficult to balance but nice work though +1