Tere are so many optional rulebooks in 2nd edition that you could probably find one that allow wizards to get weapon specialisation...
The only things fighters have for them is specialisation, if you give that to the ranger you make them overpowered, and you strip the fighter of his only talent.
If you want your Ranger to becaume a perfect archer, have him dedicate all his time to archery until he has mastered it. (4 fighter level) Then he can resume his training as a ranger. (more ranger levels)