Overcompensation is definitely a key word in this case, though I can't say I mind it too much, because I think a fursona can be something you want to be more like yourself and how you want to be perceived, as opposed to just your actual self with fur and animal features. Now, when someone goes and makes their fursonas fifty feet tall with bulging muscles everywhere, they're definitely just overcompensating.
When it comes to species, I strangely don't mind the over-use of some of them when I think about it. I really like foxes and wolves as animals, and if somebody feels a wolf or a fox represents them best, more power to them. I almost admire the ones who represent themselves with something like a red fox in a T-shirt and jeans and feel like they don't have to be any more unique than that.