JRE

I cannot say how Godunya turned into the official Dragon rune (and most people still call it the Godunya rune), but all holders seem to be in the far east. I have a nagging feeling that 30 years ago there was a different Dragon rune but I cannot find it anywhere.

So I would use the Dragonewt rune as a sign it is a stunted draconic path, and in that case, as you say, there is no need to penalize users as they will not become a Dragon when they reach 100%. Anyway, true dragon mystics also need to get the Infinite rune, so there is something else involved besides long meditation. 

Or the true Dragon rune is Infinite, and the others are just different ways to approach it. 

I like the different ways, and as I currently play in the second age, it may be quite useful, which is why I commented. The campaign probably will move to Pavis from Kethaela. Another front in the EWF - Middle Seas Empire conflict. One of the players is a jrusteli that just got illuminated in an Orlanthi heroquest, as Orlanth Dragonfriend cultists interfered with a traditionalist quest that he was attending as Issaries silvertongue (his cover among the barbarians). 

Probably just a nitpick, and it is a great idea, but I would have the cults refer to a false dragon rune, rather than the true dragon rune. Something like Godunya's rune, or even the Dragonewt rune, as going that path you get easy power, but you deviate from the true draconic path. Alternately you might need a mechanic where you lose 1% of your Dragon rune each time you roll for a spell or power.

Reflecting a moment, the Dragonewt rune seems more appropiate for Dragon Pass, as it is a recognized rune but clearly not the direct approach. Lacking reincarnation, humans cannot follow the Dragonewt path to its conclusion, but they can yet get power out of it. That keeps Godunya's rune and its potential false dragon status to Kralorela.