While I am grateful for the XP and loot increase, it concerns me that the event will happen concurrently with the existing bot problem. I'm concerned that the server will have a hyper inflation problem, which in turn hurts user journey, which then leads to a decrease in the server population.
From a top of the funnel perspective (think of a funnel wide at the top and narrow at the bottom with fresh new accounts making the top of the funnel), new users join the server, hit 99 then goes on the market to improve their equipment. Currently, for any legit player, buying any decent gear with desired stats is getting more and more unreasonable with inflation. Most nicely stated weapon/armor would be purchased at an unreasonable price from a bot farmer at 40 million zeny. That user can then decide whether they want to farm 40M zeny, which in turn most would give up and quit. This effectively limits any population growth and well geared players quitting due to low activity.
Analyze what the retention rate looks like and compare against cohorts based on new account creation by month. It should give you an idea as to how fast that top of the funnel is shrinking.