Kappa - fact - the 737 Vref speeds for Flaps 30 are 1.3 Vso. Vref for Flaps 40 is 1.25 Vso.
The reality, at least for Flaps 40 Vref, is that the Vref speeds are artificially lower than typical Vref speeds (1.25 Vso instead of 1.3 Vso). That's exactly 180 degrees from the post you reposted.
The plane is 'hot'. It's from the stall speeds, multiplied by either 1.25 or 1.3 Vso, and not some 'added' pad. Unless the stall speeds are deliberately(artificially, ie 'pencil whipped') increased, which I doubt.
Never heard anyone mention rudder issues and havn't observed it either.
The report stated Vref was 148 kts. That is Vref for Flaps 30 @ max landing weight. The initial reports state that the landing was at Vref, and not some Vref + number.