Honestly, I don't see much that catches my eye as a flaw in this... I think it looks beautiful! My only suggestion, would be to have all four tones on a paw, I personally think it looks a bit better that way. The only other thing, is I would have the eye glare, closer to the top of the eye and more toward the left instead of the very middle. Other then that, this is a lovely drawing.
I don't really like Leafeon or Glaceon.>.> The concept of Leafeon is good, just it's appearance doesn't look right to me. And technically, Vaporeon can learn Ice-type attacks, so there really isn't a need for Glaceon...>.> But oh well.
Are you excited about the new Eevee evolution that's going to come out for X and Y?=3