I thought of this the other day and while I certainly don't expect the guys at Ultima to impliment it, I just thought I'd share it.
"Germ Seed": It would work alot like Gene Flow and can be used on any non-rare sword or shot at max grind. You would need to be level 150 to make either regardless of weapon used. Using it on a sword would transform the weapon into "Pollux's Axe" and using it on a shot would make it "Castor's Cannon". For those of you who don't know, those were the final bosses from Episode 3. The weapons would retain the %'s of the weapon transformed, but here's where it gets interesting. It also inherits the ABILITY from that weapon too! So if you just use it on a sword with 0/50/0/50/50, it'll have those %'s but no ability. Use it on say, a Hell Sword and it'll have those %'s and the Hell ability! Same for the cannon too, which by the way would work not like a shot but like the Photon Launcher. The abilities would also be unreduced. This makes it interesting as you can somewhat customize the weapon itself! Berserk, Gush, whatever you may want! It's almost like a different type of S-Rank! However they'd have next to or no grind potential. But their ATP would be comparable to the PGF weapons.
The Germ Seed would drop during an event of sorts, probably from the Episode 4 bosses. This could work one of two ways. 1: All versions of the boss can drop it, but Shambertain has the lowest chance and Kondy has the highest chance. 2: There's two Germ Seeds, one for Pollux and one for Castor. Castor drops from Shambertain and Pollux drops from Saint-Milion, with Kondy dropping both depending on your ID. No matter what, they'd all drop on Ult only and the bosses would be buffed a bit, defense wise. Attack wise, they're pretty OP.
Well, there's my idea. At least it provided an interesting read huh? Again, not expecting this to happen. The skinning of weapons alone would be a task.