I've never had a problem with boss arenas. If there is ANYTHING that needs to be in an arena, it's the boss battles. The thing is, they could use variety while designing the arenas. Platforming, interesting topoography, and scenery you can interact with. It shouldn't just be a large square, rectangle or circle room/floor. Do something interesting, dammit!!
That being said, arenas are ONLY for bosses. They should never be used for common enemies. LoI and CoD did that, and LoS did that in both the first game and MoF. CV should be an arena-less action-adventure game. Who cares if OTHER games do it? It's one of those parental moments, "So, your friends jump off a bridge, does that mean you're going to do it too?!".

That and QTEs!