Depending on how loose one wishes to define "arena", it could be said TW2 already had a couple.
I honestly don't have much an issue with arenas so long as they're well implemented, plausible or (barring the aforementioned) minimal/optional.
What isn't a cliché in an rpg? Taverns? Dungeons? Towns? Brothels?
I have to agree with you here… But don't forget dragons, they're
the ArrPeeGee cliche staple of choice these days.