Yes, there's a lot, but believe it or not it's… less than you think?
There are four main plotlines set up for TWOW:
(1) Essos (Dany/Tyrion/etc)
(2) King's Landing (Lannisters/Tyrells/Dorne/Aegon)
(3) the North (Greyjoys/Stannis/Davos)
(4) the Wall (Jon/Bran/Mel/Others).
Then there are the more minor TWOW plotlines -- (1) Sansa in the Vale, (2) Arya in Braavos, (3) Jaime/Brienne/Stoneheart/Freys in the Riverlands, (4) Euron/Sam/Jaqen near Oldtown, and brief appearances from (5) Aeron and (6) Hotah/Darkstar.
In Book 7 it's evident how things will converge further. Dany's landing is a massive gamechanger that instantly makes everything in the south about her. Meanwhile, the Others will make the Wall and North plotlines converge in book 7 or even sooner. Eventually the two massive plotlines of North and South will themselves converge, with characters like Arya and Sansa showing up to play their long-planned roles in the endgame.