Rangers aren't supposed to be a dedicated archer class. Other classes like fighter or rogue can build to be specialized archers just like a ranger can build to specialize in melee. So I don't really see why rangers should be able to get special utility out of magic arrows.
That said, I do think consumables in general need to be toned down in their availability. My Githyanki ranger can be just as good an arcane caster as a wizard due to the sheer quantity of scrolls you find.
Scrolls and special arrows should be more rare. You shouldn't be able to count on having them as a part of your general strategy. If you have an acid arrow you should want to hold on to it incase you really need the acid damage because you're not guaranteed to pick up three or four more before Act 1 ends.
Ensnaring Strike also could do with being better as a spell. It should go into effect on your next hit rather than wasting the spell slot when you miss.
