Is it just me, or does riot seem to be ignoring a couple of champions that have a only one skin, & are also about a year old but keep coming out with some skins for champions that already that have a good amount of skins for them. The champions that i am talking about are champions like, Zed, Nami Quinn, Rengar, Kha'Zix, & Zac.
Bubblegum 
Scuba 
where valor is a manta ray
Firefly or praying mantis 
As nice as skins can be, I think the focus for the artistic crew should be on VUs and reworks. I'd rather see Karthus not look like a swaying blob of a lich, or Sion not look like a clunky, axe-wielding Hulk ripoff.
Beyond that, I think the champions you listed all have relatively nice launch skins, save maybe Nami's.
They don't ignore them. Rengar is currently on the skin work, his skin comes very soon on the PBE. I think his codename/skinname is "Nighthunter Rengar".
Riot said that 2014 will be the year of Reworks. So no hard feelings if some Champions are leftover. This year isn't over yet, there will be 100% some new skins coming - like Void Fizz.
They should also make a farmer Sejuani skin, riding a big pig.
