Oblivion had a fun little Arena to play in. Figuring Nords love to fight and show off how strong they are. You'd figure they'd have an arena some where. So why was the Arena not considered in Skyrim or better yet, why was it not considered for the Dragonborn DLC or a DLC that has an Arena with radiant quests that had matches? I'd go Gladiator in Skyrim. Just wondering why Bethesda never considered it.

there was going to be an Arena in Windhelm.. never made it into the final product

I think Arenas don't fit that well into the Nord culture. Too organized and sportive, and really arenas are about money, slaves and royalty. Nords in general view their countrymen as equals and are not so keen on class distinctions and the pomp and non-sense of slaves fighting and competing for their freedom, or money.

Besides, Nords choose to actually battle their foes and tell tales of it, or else simply brawl in the streets like real men, not some phonies in gladiator shorts!

I guess that's one way to rationalize it. But, truth is, an arena was planned to be in. The assets are even in the construction set. A couple of modders put in an arena. You have to have a PC though.