The thing that is telling, is there aren't many people clamouring for him to start because they think he is ready (which we've seen happen in recent years with some of our academy graduates). It's the "can he be any worse" crowd that are making the most noise. The reason is because we broke the shiny toy we got two summers ago, and we broke the shiny toy we got last summer... now we are looking around for a new shiny toy to break.
The first team isn't set-up for success. In recent years it's felt like we've been 1 or 2 players away, so someone like Mainoo, Garnacho or the other guy, coming in and offering us something, felt like it could be impactful. Right now I feel like we need more than a top-level striker to fix our problems, it would certainly help, but there's so much more that needs fixing. We are trying to add the cherry on top of the cake before we've even baked it.
The biggest thing for me however, is even if he is ready right now (which I don't think he fully is - as someone who has watched every televised minute he has played for us), he'll still be ready during next pre-season. I've heard of and seen 17 year olds being played too early. Never heard of one being played too late.
There's a reason we blood young players during pre-season. It's a relatively low pressure and away from the spotlight. It also gives them a chance to train with first team players and feel like part of the group, build up some form of chemistry. I'm not interested in potentially hurting any players development to alleviate some fans boredom.
I also don't understand those who say that playing him too soon "can't hurt". We have seen so many examples, in our current playing squad of how seasoned professionals performance can wildly fluctuate based on confidence and other off-field issues. I think a poor experience in the first team could absolutely set him back a little. There's also a large group of fans from North London (and every fan who is old enough to remember the Fergie era), who would love nothing more to see this kid fall flat on his face. And will be there with the horrific abuse that we seen last September if he does.
If management (the people who work with him day in, day out) think he is ready tomorrow then that's excellent. Otherwise let him be.