So before Revan it was diversity and everyone had a chance but now that has somehow changed.
As somebody who does not have Traya or Revan I think that at least 95% of top 100 before Revan were either Traya or Palpatine lead Sith/Empire teams and that is now diversity that is same team depending on whater you had Traya or not.
NS were nowhere near top 200 and they just made resurgence due in fact that there are Bastila and Revan teams out there.
Now I think that arena needs improvement and the first one and only one for now would be to make payout once per day per shard perhaps at the same time game is updated (daily activities) and that would make all those battles more meaningful and achievement worth something.