There is little difference qualitatively between "devel", and "dev". A
2-char difference is trivial

Other factors that should be considered, are existing standards, and effort
involved to go in either direction.
"devel" is in essence, our de facto standard, and has been for some years
now. Surprising our users by reversing defacto standards is usually not a
good thing.

Because of that, there are only 6 "dev" named packages.  If the goal for
the new naming standard is "[to converge on standard naming for our
development packages]", then speed of convergence to a standard is useful
to consider.
It should take only a matter of days, to convert the 6 packages to "devel".

In contrast, it will take vastly more effort, and most likely months of
real time, to convert the existing 120+ "devel" packages, to "dev"
packages. During that time, our naming will actually become LESS consistent
than it is now (120 vs 6), until the convergence work is completed