Can a grooved runway ever be considered wet?
IMHO, yes. Any runway which has a reflective appearance should be considered wet.
Even if grooves or a porous surface are designed to keep the surface well drained, they can be blocked with dust, dirt, rubber, etc, or ‘dammed’ by crosswinds.
I recall that JAR-OPS did allow a dispensation for a wet grooved runway to be considered as dry, by equally my memory suggest that this has been repealed. Similarly I cannot find any reference in EU-OPS 1, neither any guidance material (AMC) for the latter document.
Background refs; UK AICs 14/2006, and 86/2007