Some little feedback from me:

The event is decent, I enjoy doing it.
I dislike the lag inside the zone, why did you make it the same zone as Delve? We need new areas and not reuse the old ones.
Larger groups aren't penalized as heavily compared to lower numbers, which I am thankful for.
I can forgive the random augments as the game needs something with longevity atm. I think we need more events where drops aren't as plentiful so we have more things to do than just the current flavor of content for that month.
Please, PLEASE, remove the stupid weaponskills that take off players weapons. Why in the world is this here when this very same update removed those annoying aspects from other mobs? My aftermath gets removed every time and it is ridiculous.
I like the design of the big Velkk mob, more unique models please.