Illumination is an awful fit for Zelda and here’s why:
illumination can’t write complex stories, after Despicable Me 1 (which I’m not trying to imply is complex) they just stopped trying to write (good) character development or deeper themes or anything of that sort. The reason the Mario movie worked is cause Mario has such a simple story that you can get away with a movie that’s basically just fanservice with minimal plot, and I liked the Mario movie, but, my god, you just can’t do that with Zelda! There is so much more interesting lore and plot that happens in Zelda games than in Mario games that I don’t have faith in illumination to tackle. Also illumination’s artstyle does not work with most of Zelda’s artstyles! Illumination’s artstyle can’t replicate the dark art of twilight princess, or the ghibli inspired look of botw or totk, etc, Truly the only artstyle that could work with it is The Wind Waker’s but even thats a stretch. Now, I get why Nintendo chose Illumination again, cause they made them over a billion dollars last time, but almost any other studio would’ve been a better pick for Zelda and I just don’t see this movie being good with illumination at the helm.
TLDR: Zelda + Illumination = bad #
I think it could be an exception with Nintendo simply because I expect Nintendo to exert a ridiculous amount of creative control upon them, but I'm not sure.