Just a thought: Possibly a weak addition but:
Regional Knowledge: When you enter an area, you have some idea of what sort of creatures are in that area:
Practical application: When you enter an area, perform this check, and the ranger will list potential creatures in the area
I find that the biggest thing in BG games is knowing what spells to memorise in advance. Usually it is a quick reload when I find out what I am facing!
Rangers could fix this with knowing in advance what creatures are in an area and then can dictate what spells you memorise.
Just a thought!
Some other thoughts with rangers:
Subclasses that specialise in: Archery (already done); Spell casting druid style; better 2 weapon fighting skills
I loved playing ranger from a RP perspective (PnP) but did find them a little lack-luster in my BG games, so didn't play them. In saying that I prefer dual weapon ranger fighting.