One of the reason of events to begin with is to entice people to play..
if there's an event, say, 2x base exp this weekend. you're much more likely to play to get some good levels, than if there wasn't an event. especially since it's the weekend.
but you also can't have the same event every weekend, otherwise it both lose meaning and gets boring.
So here we go. We have a different event every week with a rotation.
This way - you get the best of both worlds. If you miss one event, you know soon you'll have another chance (usually next month or two), and if you have the time on the weekend, you can play for sweeter perks.
It's the exact same reason why Monster Park gives more EXP on Sunday, why GMS has "Sunny Sunday" perks, etc.
I vote against implementing this suggestion.