I'm sure we all can agree that we appreciate the event! It is kind of obnoxious though on how often the bosses spawn, at one point I had 3 spawn at the same time and it's just kind of a nuisance to deal with after a certain point. Additionally, the bosses have such a height that they knock over leechers and cause them to die. Obviously not intentional, leechers will just have to be more mindful of ladder positions (noticeable at Ulu 2). Suggestion: Maybe even make it so that one boss spawns per map at a time? Not sure if this can be implemented.
I don't mind the bosses spawn rates. But I guess thats because I have 2 NLs and I can post them around the Petri map to deal with them extraordinarily easily. I think mage ults should do more than 999 damage to even the playing field though. Would make them much easier to handle when you are leeching people.
I think the issue isn't with the spawn rate, it's that the pumpkins become quite worthless to anyone who does even light grinding. If pumpkins can be exchanged more than 3 times a day, or can be exchanged for say more candies, you wouldn't mind killing more event bosses. Personally I have about 70 pumpkins now and the bosses are starting to be annoying too. I have to take time off leeching to kill them, if not they will keep knocking me back or prevent more mobs from spawning. And I get 3exp and a useless drop :s