The problem is that these are light VU's.
Very light like Kassadin/Alistar.
And these updates are more focused about gameplay and pushing them out as soon and good as possible.
Riot ignores stuff like new particles, new animations or new voiceover to mainly focus on gameplay.
Some projects like Taric, Poppy or Sion are something comepletely different.
They kill the old champion and basicly say "We take a lil aspect of gameplay and visuals with us that fans love and create a complete new champion with it.". This is basicly like releasing a new champion because these updates are much larger scope than Fiora, MF and Shen were.
You are right Riot could take their time to even give small scope updates recalls, but their goal (which we can't change) is to release these low scope updates as soon and healthy as possible, just to keep them consistant.
There are basicly 4 types of updates ATM.
- Class Updates (No VU's just gameplay updates focused on classes. Juggernauts, Vanguards, Mages etc.)
- Light VGU (Main focus on gameplay, small VU to fit the overhaul theme of the game.)
- VGU (New model, new gameplay, new animations but overall not too much theme changes (even though the visuals will change quite a bit).)
- Relaunch (Everything gets a overhaul and sometimes everything needs to go in order to achieve healthy gameplay and cool champion design)
Well and as said recalls come only with VGU's and Relaunches.
As example all 3 champions that will still get reworked this year will most likely get recalls and animations as they are a much larger scope and have a lot more problems than champions like Shen or Fiora had. Ryze will be a VGU (GP/Trist level), Yorick will be a Relaunch (Poppy, Taric and Sion level) and Warwick will also be a Relaunch (Poppy, Taric and Sion level). We can't really change the decision of riot to not give recalls to Light VGU's, but we should be grateful that some champions do even get updates as other ones still cry in a dark corner of overnerfed old champions (
).