My Theory on the Next Rework
Riot has said that after the Mage Update and 
Yorick, they have every intention of giving 
Ryze a GP-level VGU and one more champion this year.
So far we've gotten confirmation that four of the biggest offenders aren't getting one this year; 
Urgot, 
Warwick, 
Swain, and 
Evelynn. All of them are strong contenders for next year, but what does that mean for this year? Well, let's look at the common criteria for a VGU:
Old, outdated, and generally lackluster in-game model.
Unfocused or one-dimensional gameplay kit, with minimal room for outplay, interaction, or other displays of skill and gameplay.
Generic theme and characterization, lacking depth and connection to the lore of LoL or its setting.
But given that they've already got Yorick and Ryze underway, the champion is likely to be someone who isn't so out of whack that they require a rework of Sion/Poppy/Yorick level; more of a 
GP level "modernization VGU" where parts of the kit are already pretty good or iconic enough to keep with a bit of tweaking and more cohesion, while others can be thrown out or entirely reworked for a more unique and satisfying gameplay experience.
What does all of this mean, in my humble opinion? Well given Riot's recent work, I'd have to say that, depending on how you view Riot's history with VGU's....
"Getting kicked into a well is the least of your worries."
Taric kit, where you really had little room to prove your mastery of the champion. 
Shen too, who was basically a battle of stat-check in that you could either fight him or you couldn't.
Nocturne for example could do with some serious visual changes. That ugly-ass shadow tail....
fits most of that criteria. He's a pullbot and that's all he's good for.
Talon. Who, in comparison, is more likely to be grouped into an assassin class update than get a full VGU. So that makes Blitz quite unlikely.
might be the final rework this year, because he needs all the things that they mentioned including new lore