That is an atrocious number for Snyder. If you're an incumbent at 43%, you're not in a very good position. If you're within the margin of error and at 43%, you're really not in a very good position. The good news is that the GOP wave is building and it may be enough to pull Snyder and Walker over the line in races that they would not otherwise win.
There is no proof that there is a GOP wave building. Everyone and their mother could tell you 4 years ago that there was going to be a GOP wave. Right now the House Generic Poll is all over the place and governor races will either be a wash or a small DEM gain. Senate geography is the only reason there is the optics of a wave.