If they follow the manga for the next arc, it will need to be either:
1. Longer because (Manga Spoilers):
2. Need to shorten the next arc and quickly progress to the arc that follows that arc. My reasoning (Manga Spoilers):
I would much rather prefer option 1, as i really like every single arc in the manga and thoroughly enjoyed the anime. But i know that many anime viewers are looking for that action, and while i am one of those guys who is an action fanatic, i really want them to explore every arc the manga has to offer thoroughly regardless of the content. Option 2 may be the better option as a whole since it would probably appeal to a greater fanbase (something i really don't want to admit to) since it would give us the necessary information and quickly transition into a more appealing arc for the anime only viewers.
Of course, i am generalizing here, and also being extremely selfish when i say i want them to fully explore the backstories. I just tend to get into a ton of conversations with people who are anime-only viewers who watch anime because of the animated action so i generalize a bit here, but i know that many anime-only viewers watch the anime for the complete story of whatever genre that catches their fancy. So i do apologize for generalizing, but im just looking for the best strategy to appeal to the fanbase as a whole, manga readers who want the anime to follow the story to a T and anime viewers who want the complete package as well as the awesome action packed scenes that keep them entertained.