Imo, these combat styles have a large potential, because you can give the ranger feats without him necessarily having the prerequisites.
Here's a couple funky ideas Ive been tossing around.
Classical:
Rangers Toughness: Roll d10 for Ranger hit points instead of d8.
Medium Armor Proficiency (and all ranger abilities function in medium armor)
Heavy Armor Proficiency (and all ranger abilities function in Heavy Armor)
Druidic:
Woodland Stride
Wild shape 1/day
Wildshape 2/day Tiny and Large
Barbaric:
Rage 1/day
Damage Reduction 1/-
Greater Rage 2/day
Technik