I think from the ending of Suikoden III, Luc is a complete goner. Which shouldn't surprise too many people as Luc was infamous for "dying in battle" repeatedly in the first two games, now the guy's actually gone. As for revival, it won't happen, as many people have stated Leknaat can only do that process once and used it on Gremio. However:
Luc's True Wind Rune is missing, but it's not farfetched that Harmonia will seek it's whereabouts to regain control of it. As someone else stated you might se a "second" Luc, in the form of a clone vessel not unlike the original Luc and/or Sarasai.
On the same token, it might not be a simple process to just "make another clone" to hold the rune and expect to have the clone under Harmonian control; as Luc stated in Suikoden III the True Runes hold the memories of past bearers, and so this would include Luc, and thus another clone would simply be far too likely to bend to Luc's will upon the revelations of the Wind Rune as to the truth about said clone's existence.
Since none of the Suikoden games have yet to go forward anything and everything is up to speculation, however at this point Luc as you knew him is dead, and it's highly unlikely he'll be back as Suikoden deaths are pretty final; we don't see Culgan and Seed walking around anymore, either.
It'll also be interesting as to how Sarasai is now affected knowing the truth about his existence. Still it looks like it'll be a while before we see any aftermath to Suikoden III.
What is most important to you? Will you give me the happiness of taking it away from you?