While I sympathise with trying doing more with the ranger-class, I dont think what they need is a combat bonus, and giving out +2AB (offense) or AC (defense) seem a bit high. Why should they be better at fighting whith weapon focus than others?
Instead maybe focus more on their role as rangers, that is their wildlife/survival skills. Let them find berries that for a short time boost their abilities or something else that has with survival in the wild as a theme. Perhaps boosting the trackless step feat at some point (like at level 8 or 12 or something) adding something like the barbarian fast movement (if possible, I have no idea how to modify anything, I am just suggesting) in wilderness areas. That would be very ranger-like (hunting down prey, running from enemies while stopping and sending arrows after them)
If combat bonus is aplied (AB/AC) is it possible to make it dependent on being in a wilderness area? To immitate that the ranger was better at finding his footing and using his surroundings in the fight. That way you would have rangers that "ruled" combat in wilderness situations, but was more average in towns or indoors.
So my basic thought is: if the ranger needs a boost, somehow tie it to something ranger-like.