As much as I hate to say it... Riot doesn't give a single fuck how long it's been since a champion got their last skin. All they care about is what makes the most money. It's why champions like Lux, Ezreal, Miss Fortune and Ahri have over 10 skins.
Ornn, Nautilus, Skarner, Kindred, and even Taric aren't popular. I mean, Kled has to wait for 2 years before he got one, and even then it was a half assed halloween skin. That's it! So I won't be surprised of many of these don't see a new skin for another year, while riot continues to cater to champions that have done well for them. Lee sin is getting his 10th skin (it's a 2 parter, both Dawnbringer and Nightbringer) and Nidalee is also getting her 10th with the upcoming Dawnbringer. Also who's excited for another Karma skin? Not me. Fuck that champion.
But Soraka's getting some sick skins, and she's my favorite champion, so I'm happy for that. Still annoyed about the massive favoritism Riot shows for their champions. They don't even try to hide it either.