And that can be boosted by +1 more if you take the "Synergetic"-something feat in Races of Destiny. (I forget the name; it's got a half-elf prereq.)
There's a feat in one of the Complete books (Adventurer?) that gives a +4 to bardic lore checks. That ability is similarly low-powered and mostly for character flavor, much like W.E.. As a DM, I could justify the same sort of feat for Wild Empathy. Or at the very least, a simple +3 Skill Focus.
(And although it misses the gist of your query slightly, :\ you can always take the route of increasing your charisma to improve that attribute modifier.)
It's a bit of a round-about way, but there's also a few Incarnum melds that'll increase it. Take the Shape Soulmeld feat and get either Beast Tamer's Circlet (+2 Insight Bonus to Handle Animal and Wild Empathy checks) or Unicorn Horn (+2 Competence bonus to Move Silently and Wild Empathy checks). A lot of DM's dont accept Incarnum though so it might not apply in your case.
There are enough examples and similar ability modifiers floating around out there that a *reasonable* gamemaster should allow a +X feat of some sort if you ask nicely. It's not as though the ability is a real game-killer.