There will still be whining and complaints of unfairness.
Trust me. Most players here just want the heroes. U can create a poll to ask the general public if they agree to have the hero unlocked at 60% instead of 100%. It's a free 5 star after all to those who can get 1. Whether they use it a not they can use it as a fodder.
Where's the exclusiveness then? I think previous events were easier as the hero involved were only up to 4-Star.
You can think of exclusive for this event meaning any future event like Christmas or what, this unit won't be available anymore and only those who participated and meet the criteria. This kind of exclusivity to me is better than an exclusivity that even when one participated but still cannot hope to get it like your dear friend who spend the pumpkins but can't get anything.
So players who join the game late, they won't be able to get the this hero which make it exclusive. I think people can come to term with this exclusiveness just like leandra where she was advertised long ago. If people still miss Leandra then nth can help it since she was there for grab since more than half a year ago.