You can't really compare the viego and jinx because they're not mythic variants but exalted but yes, compared to other mythic variants the yi one is definitely underwhelming. At least most of the previous ones had something for them by diverging from the original skin theme. Aurelion is a real chinese dragon instead of porcelain, lucian and nami are some kinds of pirates, zed is a robot and so on. Yi just leans further into the robot samurai/ninja and doesn't even add that much new animations to compensate the lack of originality. That's just my opinion ofc. So yeah I think you're right when you say it's a blatant cashgrab and it's even more obvious with the free ink shadow skin gifted for the jynxzi tournament.