Sorry but no,I don't agree with it,rusty blitzcrank is entirely different,it was a normal skin,available all the time,it was simply removed because it didnt change anything aside from the darker look( rusty wtv) was pretty poor and it is why it was removed.
Snow bunny nidalee is something that is part of LoL history,part of the snow showdown in 2009,that is 3 years,it was only available during that time,and makes the rarity of it very special for people like hotshotgg and a few more.
I'm all up for it if it was a skin that was available all the time and then ended up being removed ( leopard nidalee) for example,but skins that were available for short time in the beginning of LoL? I do not agree with that