Personally I'm kind of split on Monolith's design. I think their character design has a tendency to very heavily cross some decency lines, and I'm not even the type of person that would normally notice stuff like certain Fire Emblem designs or that one thigh fetish thing without people actively pointing it out to me. On the other hand, their landscape design is very very creative and top notch and tends to be lively with big immersive environments if not necessarily the highest detail if you really get up close. Now, synergy with a main Nintendo team is key here because core Nintendo is the opposite, heavily conservative design wise and super big on attention to detail on the small scale but really misses the forest for the trees at times, figuratively and literally.
Monolith slipping into more of a development co-op role on the next Zelda could turn out pretty nicely because Xeno games have a lot of the things people complained about BotW not having such as huge varieties of enemies, fairly complex plotlines, and a good number of sidequests. Meanwhile the core 3D Zelda team is almost certain to polish out the flaws in Monolith's design methods until their input is smooth enough to show a reflection. They make a good yin-yang team in theory, so I'm more than up for seeing them with some more equalized input.
Considering the complaints people had, tag teaming might very well make a game that tops BotW. No such thing as a guarantee when it comes to video game development, of course, but they really cover each other's weaknesses and have unique strengths to bring to the table. Granted, we know this in the first place because they're hiring new staff, so maybe that'll throw a wrench in what we can expect if anything at all.