This affects her team fights and her jungling. Fixing that will make her jungle far less dangerous. Simply add the first mini frost to her W. Stand in it, get frosted.
Amumu, her closest related Tanky-Jungle, has better base health. Better mana regen. Slightly better Health regen.
Her kit is very close to workable, but clunky and unlike pretty much any other tank in LoL offers no sustain or damage reduction.