Rangers make an excellent secondary class for folks wanting to dabble into
Beastmastery or Marksmanship.  Wilderness Survival also provides a great
variety of skills covering everything from healing to damage, for a few skill
points.  However, secondary Rangers lose the all-important Expertise attribute.
Some primary classes compensate for the attribute benefit by having their own
Energy management attributes like Soul Reaping for Necromancers or Energy
Storage for Elementalists.  Secondary Rangers miss out on most of the benefits
of having effective Expertise-based skills like Throw Dirt or Whirling Defense.
This can be alleviated by Primary class-specific defensive skills (like Ward
against Melee, Distortion, etc.) or by using Dryder’s Defenses (which is
available to anyone with a high Wilderness Survival attribute).