What should you replace your World of Warcraft Ravanger with as a Hunter

It depends on what you want to do with your pet. A ravager is considered a "cunning pet" which can be good for PVP and solo leveling. Other cunning pets include bats, dragonhawks, serpents, sporebats, nether rays, birds of pray, wind serpents, etc.
If you prefer dungeons and raiding, you may want to train a ferocity pet. Ferocity pets are devilsaurs, raptors, wasps, cats, hyenas, spirit beasts (rare), wolves, moths, etc.

If you prefer for your pet to be your tank (great for leveling and solo adventuring) you will want a tenacity pet. Tenacity pets are bears, crocolisks, scorpids, gorillas, boars, turtles, crabs, rhinos, etc.

A good guide for this (including where to find tamable pets of these categories) is http://www.wow-petopia.com