So far both recurring events can easily be completely completed within the first run of the event. This would make sense if it was a one-time event like the Rakghoul or a rare event that occurred once ever 6 - 12 months, but for these once every 1 - 2 month events it makes absolutely no sense. IMO if you are ever going to make another event that you intent to recur regularly (which I'm definitely not saying is something the game needs or wants) then one of following should be done:
A. Put 3 - 6 times more content into the event making it impossible to finish the event in 1 or event 2 runs of the event.
B. Make it so you can complete everything in one run, but add completely new stuff with each run.
C. Make it much rarer like once or twice a year.
Here's a thread showing people completing the BH event easily in it's first run with some people doing it in like 2 days:
I would also love it if you fixed the BH and Gree events with one of the listed ideas.
Thanks for listening.