Rangers spellcasting is very limited in usefulness to begin with and ranger characters are generally martial classes so most players who build rangers find wisdom as a tertiary stat. Unless you are playing with a high point build it's unlikely a ranger will have a high enough wisdom to cast 3rd and 4th level spells.
I suppose one fix to this is for the ranger player to invest in stat boosting items. Personally, I don't care for the idea that a player needs to lean on magic items to enable their class features.
I can understand bonus spells being tied to wisdom but I think rangers should be able to cast 3rd and 4th level spells regardless of their wisdom.
An alternate would be to switch the rangers spellcasting stat from wisdom to intelligence or charisma, similar to the way the paladin's was switched to charisma. Rangers are the other skills based class and intelligence would allow them to boost their skills. Charisma benefits the rangers handle animals and wild empathy class abilities.
Then again wisdom helps their will saves, perception and survival skills... hmmm
