I don't see Rusev as stale at all. If anything, he's showing what it means to be human.Funny you mention the show being stale but still like Rusev. He's lost any and all momentum as a heel imo.
Rusev faced rejection from Lana and has, accordingly, acted small and petty.
When people are dumped they don't feel empowered and often have to step back and reassess their own priorities.
I can't recall the last time I've seen a WWE character actually roll out on live tv and act like a human being instead of a f*cking cartoon.