I can agree with caveats that the Mario movie is "good," but even if those caveats didn't exist, even if the Mario movie was the best thing ever, that doesn't really change much.
The Mario movie is true of every Illumination movie I've seen, that it's heavy on comedy, light on plot and character depth. That can certainly work for Mario, it can probably work for their other IPs, that isn't what I'd want for a LoZ movie. Yes, LoZ can certainly be light-hearted, but even at its most light-hearted, it still takes itself more seriously than Mario does. Or even that aside, I can't think of any Illumination films that would match the style that LoZ usually executes its stories in. I mean, this is a studio whose most popular characters (commercially at least) are little yellow mutants that never stop babling, while LoZ's protagonist is a person who barely talks at all.
So, no, I'm not filled with confidence. At best, I could see it being a good movie, if not a good LoZ movie. And while Twilight Sparkle demonstrated that I like the idea of a LoZ movie, I cannot, for the life of me, understand why anyone would choose Illumination unless you factor in Mario, and factoring in Mario doesn't really say much for LoZ. There's certainly Nintendo IPs that Illumination could fit in for, IPs like LoZ, Fire Emblem, and Metroid aren't among them.
(Well, maybe Fire Emblem these days...)