Been testing out the bow and staff and I'm still indecisive over it, I can do a skyrim and stealth sniper fuckers for massive damage with the bow but that slows me down a bit, magic is more flashy and generally had better crowd control if i used the fire staff and books.
I'm still not sure where to go combat wise, Is the bow a good physical weapon, apart from the fireball what's the key differences with Fire and water magic.
Water does a lot less damage with the mainhand and offhand but it's much quicker. The fire offhand is pretty trash, low damage, and it's targeted like the bow aoe. With the delay on it, it's pretty difficult to land a hit where you want, especially since you can be interrupted while targeting. The best combo for magic is generally frost mainhand, frost offhand. The frost offhand is really the only magic that can deal with swarms of enemies that you'll face a lot in this game. You could keep fire mainhand on your toolbar for when you can afford to charge up an attack on stationairy enemies too like undead or an ambush party that you'd fled far enough away from.
The issue with magic is it requires a full wis build to stay viable in late game. If you're asking between bow and magic, bow is better just because you'll be able to do other stuff and cover for its weaknesses with melee weapons and stealth. Even putting 4-5 points into anything but wis will hurt your magic damage tremendously with the way enemy defense works in this game. You could have your damage cut by 50-75% with those points not being in wis. With the stamina system that means you'll either be chugging stam potions every encounter or dead/raped not going full wis build magician, lol.
So a stealth mage would be fairly difficult to pull off and you'd be stuck trying to use fire damage only. Frost wouldn't do enough damage anymore, you'd become a one trick pony against later mobs. I admit I haven't tried it since my first playthrough though, I'll do that now I think. I can't remember if charging magic breaks stealth. Getting to 15 as a pure wis magician is a bit painful lol. Get to watch your companions beat on skeletons for an hour and a half or so.
The bow is one of the best weapons in the game in my opinion (I'd say the best but I haven't tested the whip and some rare weapons yet). The main attack is similar in damage to the mainhand frost attack, the aoe is a bit iffy but kinda funny to use. The snipe is OP as hell when you're able to ambush peeps. As you've noticed, stealth + rock throw distraction into the snipe ability is super powerful and usually all you'll need for most mobs.
See gif in attached images for anybody curious about how strong the bow is, lol. Also some bonus dagger gifs. That you don't even need to be in stealth to stun enemies with the mainhand dagger is crazy : p The dagger gifs are Saber mainhand, Enchanted Dagger offhand btw.