I agree.
I respect that some users prefer csh, but noone proposed to remove it,
only to change the default selection. For technical reasons, many
prefer sh, and I doubt that Linux has anything to do with it (please
forbid my short history research results):
The Bourne shell (1977, AT&T Version 7 Unix) was the inspiration for
ksh (Bell Labs, 1983), which in turn has inspired POSIX 1003.2 and
1003.2a requirements for shell. Our shell seems to be a Bourne SVR4
variant shell clone (Almquist, 1989), that has evolved to include some
POSIX ksh-like features and improved interactive features.
I have no authority, but since opinion was requested, mine is that
/bin/sh as a default root shell makes sense for a modern NetBSD.