I don't agree with either the length or the art. I'm happy to read the series however it comes out, and if it's regular that's even better. Ultimately it all smooths out and quibbling about a few pages in the midst of literally tens of thousands of pages seems silly.
And the art has always changed over time, as it does for many mangaka. Maybe Morikawa is experimenting, or preparing other chapters, or currently engaging in something else in his life during relatively low key arcs. I don't really care, it's still good enough for me.
And isn't it what people have criticized already? Some claim he isn't even drawing anymore. Any criticism goes when people just want to make a spat about Ippo not boxing. As if handing over to another artist will do any good. I wouldn't be happy that's for sure, I want Morikawa's art and I don't give two hoots about whether another artist is technically better or that they think art is just a product where the artist is replaceable.
If you want a professional/client relationship, go hire an AI artist to make 20 page chapters and an unofficial storyline to finish the story how you envision it instead of waiting for Morikawa to show you his artistic vision. As long as even an AI can draw better than Morikawa, it shouldn't even be a problem with your criteria now, would it?
If Morikawa stops drawing, I would prefer it's because he himself is unsatisfied with the work and independently chooses to change things up. And at minimum if he seeks fan sentiment about it I certainly don't want it to be from a bunch of whiny leeches on an English forum. Ippo is still highly regarded in Japan by actual paying readers and makes top lists, actually increasing readership slightly compared to last year.