I personally see no reason to adjust rewards on events. There are some events I don't particularly care for, but its not because of the rewards. I just don't join those ones I don't enjoy as much. Even still I amass crazy amounts of MuhCoin from doing some GM events and usually a seasonal event or two on the daily. I get plenty to feed my HE BBG needs and restock myself with MuhPoints for the MuhShop when I want/need something like costumes or consumables.
The only thing I would change is that the MVP event requires you to be within like.. 3 cells of the MVP to hit it? Not sure, haven't really thought this one out. But regardless, ranged get like 80% of the MVPs before melee can even get close, so I sympathize with @Eneru. I wouldn't change the rewards though.
(Also in regards to MVP event.. a couple mobs that don't normally spawn, spawned. I would remove these as its possible to get items that no one else can get from them. For example a Woomawang spawned and dropped an item that you cant get except from killing a Woomawang.. which doesn't spawn anywhere)