10 years for one arc sounds pretty normal when you consider how long the sasuke arc in naruto has been going on or how many years the black organization arc in detective conan has been ongoing with no end in sight
I don't know why people are saying introducing new Stern Ritter is considered a waste of time. We all knew that there was going to be one for each letter of the alphabet. They were going to get introduced eventually. I'd rather now than later so that we can move on with the plot. As for the chapter itself. It was decent. Yes a lot more could have happened, but I like how we're seeing the personalities of the Stern Ritters. The Quincy seem a lot more brutal than the Espada.
Ooh, now I see the reason of the discord. Also, I think the other people in cloaks are the Fullbringers, and Urahara's experiment is looking like a Quincy symbol.