Well, another forumite and me did discuss a previous, more tentative version of the archetype here
Were you referring to that, or to other kinds of discussions ?
The option to swap MA for Guns is IMO really not feasible in most cases, since a good score in Martial Arts skill is pretty much mandatory in order to use many Creature Powers effectively that are highly appropriate for the concept, and a Creature Powers-Sorcery power combo is a big, basic part of the purpose of the Archetype (i.e. to be a more earthy and badass version of Ghost). So having three good combat skills (Creature Powers, Sorcery, and Martial Arts) is pretty much necessary for the concept.
OTOH, I also acknowledge that in several cases, having a proficiency with ranged weapons may be appropriate for the concept (e.g. an ex-cop, soldier, or detective Revenant from modern junctures). The optimal way of giving the Archetype proficiency with ranged weapons without ruining its purpose (i.e. default good efficiency in Creature Powers, Martial Arts, and Sorcery) would be to add Guns as a fourth combat skill. As a matter of fact, there is a canon Archetype (Abomination) that has 4 combat skills (Arcanowave, Creature, Guns, and MA), so I suppose it could be theoretically done. OTOH, some players and GMs may have serious qualms about adding a fourth combat skill according to their own evaluation of proper game balance and power level, even taking this one precedent into account.
I indeed suppose you could use Blast for either Creature Powers or Sorcery in the form of spectral guns to represent the cases where the Revenant was an ex-gunslinger type in life and his combat powers would express so. As a matter of fact, a big point of the Archetype is to fight and solve difficulties by sorcerous/supernatural powers, not mundane weaponware. This is probably the simplest way of expressing it.