We could use a small change in how these events work. To make it fair, and enticing for everyone to want to participate, we need a way the events can be challenging at different levels and reward different tier players. This event comes close to doing well, having the easy and hard modes, I love that. But, as many have said, the enrage timers are an issue. It can be fixed easily though, to appease most. The easy+hard more aspect can work well, if the hard mode can be done by mid-tier players. Not asking for it to be easy, just that it has to actually be possible to beat by the average geared person who puts in enough effort. However, to appeal to the higher-end characters I thought of a few options:
An extra timed Dynamic Quest where if you fail to complete within the time limit, you don't get the additional currency reward
An event item/orb to start a challenge mode
An event item/orb to summon an additional, harder boss
Basic event currency from the easy mode or easier dungeon.
2nd currency from the harder mode or harder dungeon.
And possibly a 3rd item/currency from the challenge version for the higher tier rewards.
Lastly, the rewards between mid and higher tier players needs to be enough that each feel it's worth doing, but it shouldn't be more exclusive items that make everyone else feel like they're helplessly missing out. Looking at the current event, I think the main issue is that there is no middleground, everyone except the top 10-15% are stuck with the easy-mode reward because after that, it jumps to a 1.3m dps check. It's clear how many people are unhappy, so maybe take that as a lesson and also keep event-exclusive cosmetics as something available for everyone who participates for 2 weeks. Maybe add the stronger consumable buffs, and occasionally tradeable ones like Chocolate Delights for the higher tier currency.
And just my opinion on the rewards, but the basic ones we always get, most of them should be cheaper by now. Not even the Hive Queen Hearts are really worth buying over Sacred Vials and Pet Packs unless you really need them, but it's still a one-sided trade off.
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Previously, I was just suggesting for this event that they leave mechanics the same or even buff them, but in exchange, nerf the HP significantly so at least mid-tier players who actually can benefit from the event rewards can participate. Depending on how long it takes, to compensate give a couple Resurgence Emblem in F10 each day for a week or two. Also add the event weapon as an illusion sometime, I'd love to have illusions of our progression weapons, and maybe some recolors.