Leaving the feet slightly above the base allows for the flocking, which will be added later, to "flow" under the feet instead of around, and over them giving an unwanted "sunken" appearance to the model's feet.I glue all of my minis with the feet slightly above the base for just this reason, and I am guessing the artist of this wolf has a similar reason for doing so.
Bases are a pet peave of mine, even if its just flock painted white I think it would improve the look, also the plastic 'rail' for want of a better word that links his right feet should be flush with the base.