I was one of those people who ranted about this in the spoiler thread also, and primarily for two reasons (1) because I didn't like the way that this turn of events appeared to be taking the edge and anticipation off of the ultimate fight between Zoro and Mihawk, and (2) because up until now, the pattern had been for Luffy and Zoro to train independently from their mentors (Shanks and Mihawk), with their mentors watching from a distance and trusting that the two would find ways – on their own -- to reach that level, too. It's one thing to become stronger and more resourceful on your own, but another to do so under the tutelage of a master who is guiding you though the process and teaching you how to think and how to react, instead of letting you figure it out for yourself.
As best I can tell, Zoro invented Santoryu -- it wasn't something he was taught, but was something that he synthesized from what he was taught. So we know he's capable of finding his own way from the start. And that's something that I've liked about OP a lot: that there's this message of independence running through it: you don't always have to be highly born; to be trained by a grand master; to be "fated" to do something -- you just have to be persistent, clever and ready to create your own luck when the opportunity occurs.
Having Zoro train with Mihawk goes against all that. It's basically saying: "oops, sorry -- looks like you've got to toe the line now, and be tutored by the current reigning champion, and learn some ultra secret techniques that were handed down from his master's master too, because there's no other way in Hell you'll be able to win."
Granted, that's not what Oda was probably thinking when he write this, but that's how it comes across. To me at least. (Feel free to disagree). So that's why I dislike it.
@Sâuza:
Which alternative options would you have liked to see (or expected) considering Zoro's training ?
(plain, simple question. No Kubo, no flame, no shit)
What would I have preferred to see? I mentioned that in the spoiler as well: I'd rather see Mihawk tell Zoro that he has no time for him, and that if he want's to get stronger, Zoro needs to fight Perona instead (this may still happen in the story, it's too soon to tell). We know that Zoro is still vulnerable to the negative hollows, and that the only way he can counter them is probably via haki. So it's a perfect opportunity to develop that side of his fighting ability. He won't need much help developing the strength side – he's been doing that against the mandrills, and can do that against any other beast on the island. In this scenario, Mihawk remains a mentor, but without taking anything away from the build-up toward their final fight together, and Zoro retains his independence.
@Aaronrules380:
TB never had Zoro swallow his pride. He was as prideful as ever if you paid attention. TB was a display of him being ready to throw down his life (and by extension his dream) for the crew and Luffy, and it's even possible Zoro thought he had a chance, however small, to stay alive (which he obviously did) and took it as one huge gamble. But from what we know of Zoro, his pride is more important to him than his life, and to show that he is ready to throw it way for Luffy is a much bigger symbol, and he couldn't do this without swallowing his pride.
This is a very, very good point.
I concede.