Hardly; Ryze didn't need as much work as Yorick. Riot has more than one rework team, and they work independently, so Ryze didn't affect Yorick at all in this. With Ryze they had a kit that's at least gonna be retained in some form and updated VFX from last year, and his theme is already solid as the muscled arcane mage dude.
Mean while Yorick needs EVERYTHING changed. His entire kit's probably gonna go and they had/have to figure out how a necromancer actually works in terms of League's gameplay, while also being that gravedigger. His story has to tie in with the new rendition of the Shadow Isles and all of his visuals need redoing for this updated, including his ghouls (or whatever he digs up post rework), which all need their own models, textures, animations, VFX and SFX.
tl;dr Ryze is to Yorick as Gangplank was to Taric. They had different problems and Ryze's are just easier to fix. In the time between Poppy was officially said to be in production and her release we had reworks be announced and completed for Gangplank and Fiora. Things aren't so binary that mentioned first = out before the next guy who gets mentioned.