There are enough sustain teams out there that can auto most of GW that I fail to see this as a problem for a long time player. I auto through every node except 9 and 11. Occasionally 6 will be an issue. But at absolute worst there are only three battles I actually have to do manually. Some days the whole thing can be done on auto. I let it auto while I'm doing something else, and walk by occasionally to tap rewards/next battle/auto until I'm at one that requires my attention.
GW might be a problem early. I hated it for quite a while. But after a year in the game it should be a non-issue.