Gen4 M.2 devices expected a certain electrical idle exit time. At Gen5 speeds, the window for signal lock is dramatically tighter. Rev 5.0 redefines the for the M.2 connector, ensuring that the tiny traces on an M.2 2280 drive can reliably hit 32 GT/s without excessive bit error rates.

However, “Version 1.0” does not mean perfect. Expect a Version 1.1 or 2.0 in the future to address:

The M.2 standard continues to support a family of form factors designed for "Mobile Adapters," transitioning from the older Mini Card standards to a more integrated, space-efficient solution. PCI Express M.2 Specification Revision 5.0, Version 1.0