I think that the idea that they had last year where you could trade in your candy for different goodie bags was a good idea but people are always going to find some aspect of it to criticize which is why there was such a big drama about it last year. -_-
I think that the idea of having a pumpkin blob boss for Halloween instead of the normal green blob would be pretty cool.
Or maybe a Halloween quest where you have to solve a murder mystery or something along the lines of that?