Overall, I'd say the Masters community in general is making this worse than it actually is. I haven't felt this good personally about a mobile developer in a long time. Sure, there is a lot of experimentation, and things go wrong more often than not (Game Freak itself is pretty notorious of this), but I think Dena is in an unusual position where they seem to be finding the right feedback to implement. I wasn't crazy about the prize box idea at first, but it's actually kind of...ok. I think it would be better if there were fewer types of items in the box (I about every week have to exchange the level 1 Strike/Tech/Support items for level 2 items just because I get so many of them, and the Pearls and Training Machines are kind of useless).
Not having the ability to max out a legendary can be viewed as a missed opportunity, but I think they may have done this to improve replayability when these events return in the future. How often have you seen events return about a character that people do not have, but you already have the character (and possibly maxed out)? There would be no reason for you to do the event again, and in some cases, you're not even allowed to redo the event. This is what I reason as to why Dena chose to do Ho-Oh's event this way. Maybe you won't get new stories when the event comes back, but the items will be there to be collected again.