There is nothing wrong with this, it's just another way of looking at this situation. You have 2 sides:
1. It's too easy, everybody got the rewards so my own reward is worthless. It has to be deleted and restarted cause we want it, but we want it to work the way it should.
2. Finally something new and fun to do, great event, I love my tmogs even though anybody else can get it as well, thank you gms.
My realist point of view: If gms decide to follow 1, you have to realize that deleting the rewards might just take an hour or so but fixing this to work the way it should means we might not see these challenges again until next year. If fixing the item scaling was so easy they would have done it long time ago. And after all the stuff molten and warmane has been through, I for once am happy we got something nice in return, it's like a gift to a community, not as it should be but good enough for me. Like the cow event LAST year, that one day of being bugged was enough fun for an entire year unlike this year when it wasn't even worth doing.