Players should be able to get role specific 'milestone' event items by playing only that role
Milestone event items where introduced last event. Players complained because you had to complete the survivor missions in order to get the killer specific cosmetic reward. It appears to be the case again this time, where players will need to complete the killer missions in order get the head piece for the Jeff outfit. I don't think you should have to play a role you don't enjoy to get event/celebration rewards, but if you do, the last reward shouldn't be role specific or a highly desired item like the new banners and icons.
This isn't about the difficulty of the missions, the issue is that some people just don't like certain styles of gameplay. You also create the problem of people playing only for objectives that aren't in line with intended gameplay. I, for example, gravitate toward tanks and healers in video games and don't get any enjoyment from hitting people who can't hit back. It's just not worth 9+ missions of killer to access the final reward.
Events should be a celebration, not a chore.