@Riot Some Inconsistencies with Ryze's Ult?

Side note: I myself like the new Ryze kit, it seems rather fun and maybe I might just play him more than I used to.

So I've been talking with a few other League players and we've come to a conclusion that Ryze's new ult (Basically Team Teleportation) isn't quite as consistent as perhaps as originally thought. There are some champion interactions that work, while quite similar champion interactions DON'T work.

Anyone who manages to find some other discrepancies with Ryze's Ult, feel free to comment and I'll add them to the list of examples!

• Ryze Cannot Ult Karthus while he's in his Passive (Death Defied), however Kalista can do so.

• If Ryze Ults Tahm Kench while He's Devourered something, TK will spit out his victim. Ryze can Ult Skarner while he's pulling someone however. Similarly, Ryze can Ult Urgot while he's ulting someone as well

I was wondering if I could get a response from Riot as to why a couple of abilities work for him, yet a couple of very similarly champ abilities DON'T work with Ryze's Ult? IMHO it seems like a bit of inconsistency to have some stuff work and some stuff NOT work.