Hm, hadn't thought about the show staff's reactions. Though to be fair I have been rather absent from all sorts of pony discussion sites for a while, so I don't know what the opinions really are. I find it hard to believe the team wouldn't be capable of recognizing what people are actually objecting to. But what do I know, maybe people are just spewing nonsense as well. Wouldn't really surprise me.
Hmm, had the rainbow power designs been more, let's say reasonable, would you find it as objectionable? I personally would like them way more, though them simply gaining some superpowers without the use of magical trinkets is a bit much for me (one of my original objections to the power of love in ACW vs the Elements). One could argue the tree blessed them with said power or some such, but… meh.
I'm not sure I would call them useless to the story, though.
Well, the box could have simply contained the Rainbow of Light which would have proceeded to annihilate Tirek (and work as another nice reference). …that went nowhere.
I am rather peeved by Hasbro having these tasteless marketing ideas and toys they simply must have in the show without much consideration. It seems even more odd after the show took off on its own. If they told the show team (or someone else who actually thinks about these things) that they need designs for new toys I'm sure they'd be happy to deliver something that would be more in line with the show and was easier to tie in to it. Then again, maybe that's exactly what they've been doing for all I know, and it was their bright idea to have a crystal tree in Ponyville rather than the marketing department's.
I can't imagine the little girls would object to better thought out colours and designs for their toys, and that would keep the whiny fanbase (that's us) somewhat happier, and more likely to actually buy the toys. Heck, give me brushables with the Gala, or reasonably similar dresses and I'd be all over those.
The effects of the rainbowification… Well, yeah. It might have an effect, it might not. I rambled on a bit about some possibilities here but with each one I realized they could simply say "eh, fuck it" like they did with Twi's princesshood in S4, so… yeah.
The tree, though. As you say, it makes it even clearer that what happened to Twi was "destiny" or "fate" or whatever you want to call it, and not something she simply earned. Which, as I mentioned above, I much prefer. But every time they imply something like that they make MMC look even worse than it was before. I highly doubt, assuming she was destined to become a princess, that Twilight would have spent her life watching tv and writing smut. If she was destined to become X clearly her life would have gone a certain path so she would become X at some point, no? Of course then we get into the area of free will and all that fun stuff, which is why I am not a huge fan of the destiny thing in general. But, assuming destiny, like the tree seems to imply, she wouldn't have become a princess doing nothing. That doesn't mean she would have necessarily earned her princesshood all on her own because of said destiny. …Hm, actually, does destiny remove the weight of both responsibilities and accomplishments? I mean, you were fated to do this, so was it that you did it on your own but it was simply foretold, or was it that you only followed the script like an actor? And does it matter for the person actually playing that part if they don't realize they are being lead around? …I shouldn't have taken such a long break. Too many things to ramble about and it seems I can't stop.
To get to the point, I liked the tree. It makes it clear what MMC implied, and flat-out said, was wrong, or at the very least not the whole truth. And Twilight having a destiny of some sort makes for a much more interesting story than her supposedly having earned her princesshood. (Well, that could lead to some nice stories as well, but I am fairly sure they wouldn't be explored in the show)