"… both crew members need to turn the trim wheel "
This should not be required in the context of MCAS. The proposed modifications suggest that new protections will automatically inhibit the trim before such an extreme offset is reached. (NPA for comment)
With regards to a trim runaway, apart from MCAS, this remains a possibility in all 737 variants and continues to depend on quick recognition and action to inhibit the trim. If not then the two handed procedure would still be required, more so in those aircraft with the smaller diameter trim wheel. (Outside of the scope of the NPA ??)
The trim runaway is a debatable point with its reliance on crew awareness and quick intervention - shown to be insufficient in the MCAS accidents, but now argued as not being the same situation - HF aspects. If not, then would the combined crew effort on the trim wheel for recovery contravene certification requirements for all 737s.