I think we'll have 10 volumes before the more "global" characters are reintroduced.
I think Oda is redoing the first 10 volumes for One Piece before they headed into the Grand Line.
But now it's 10 volumes before the it gets back to Akainu-garp-shanks-BB etc.
May I ask, how would he make 10 volumes of the SHs in the New World, without them stepping into some "major" character? (and with major I include some important person that might have not been introduced yet, and the supernovas)
I think since we are in the NW (well, at least when this saga ends) the pace of the story will be different than in first half of Grand Line. For what we know, it's really difficult to reach Raftel, as Roger says to WB in the latter's Flashback ("Do you want to know how to get to Raftel?") so I guess the pirates in the NW are not "GO STRAIGHT FORWARD", but they hang around the ocean, around the islands (we have 1 example of this in the "favorite" island of Kaidou, the guy says he goes there from time to time) because they don't know where the last island is, or they can't reach it.
So my guess is, we will know the majority of the NW faster than we knew the first half, and some part (I suppose a little part) of the series will be the SHs trying to get to Raftel, the "secret island" which seems impossible to reach. (I'm thinking the path to the island may be related to the Phoneglyps, because Roger was the only pirate that could read them and only them -for what we know- went to Raftel. SHs have Robin=advantage)