My thinking re. the 50mm is the opposite of yours. I don't find it to be a useful length on DX whereas 35mm is. It is a good 'standard' focal length whereas 50mm is a tad long. I also think the 35mm f1.8 is noticeably sharper at wide apertures. Stopped down the 50mm may win but they are both plenty sharp so I don't think it's worth worrying about. At all apertures the 35mm has nicer bokeh.
If you don't think the 35mm f1.8 is good enough I would forget the 35mm f2. Unless you need it for FX use it is simply not as good.
If you are happy with the 50mm stick with it and look to get something toward the wide end. My choice is a Sigma 24mm f1.8.