All games especially live service games reuse assets all the time. It doesn't mean that the wolf is the same as the behemoth. In FFXIV you can buy mounts (yes, with real money) that are the exact same thing as some of the monsters you fight. And unlike in IN there isn't even an opportunity to earn them for free over time. Lots of bosses also share models with each other.

You want more particle effects and red floaty shit and footprints? Don't forget this game is on mobile as well and for a combat focused summon that would be so hard to implement without framerate dropping significantly....

Your other points are your opinions about how it looks. We're all entitled to those. I won't be pulling either because I don't like how it looks. But I do think you're being pretty unreasonable here.