While I'm willing to believe maybe something got cut and forgot to be cut from the description, you just named 4 archetypes that already exist, which are rarely, if ever, reprinted in books at all? Why did you do that?
There's a conduit feat that fixes that. Throwing janni rush on this would be fun, 1 of MoMS then into shifter that specializes with gore might be ideal
I do wonder if the planar rifter is supposed to get rid of guntraining altogether? I know its elemental/aligned damage, but 1d6(and two dead levels for guntraining 2 and 4) in trade for a raw Mod is a rough trade, especially since you basically won't ever benefit from planar resistance and planar strike at the same time.
Share Spells can be replaced with Light Armor proficiency(which I dont think a saurian champion would be making too much use of anyways, being practically a dinosaur barbarian thats good at riding things.)
Ranger's drake companion(at level 6-7) and shaman's is usable, since they can hack reality with SkySwim. Even that's pretty late though.
They're bad. There needs to be a drake power feat and probably the option to forgo size increases for stat increase or a drake power.