actually i think its this reason they have no problem with Oavawhaticantthinkoffullnamerightnow is because i reconizes u as his new master basically while Paar is under no man's control. One dragon is at ur service whenever u call and one wants to go off and become the new dragon king.
Paarthurnax also hasn't killed in over 5,000 years. Odahviing doesn't want to master the way of the voice in peace, he even considers it tyrannical. He acts just as a normal dragon would, the only difference is he chose to serve you after you ousted Alduin. Were you to die, it's pretty much guaranteed Odahviing would go back to doing what most dragons do: Destroying the lesser races. Paarth at least shows promise and redemption, not simply "going with the stronger guy". He defied Alduin even when it meant he could be killed just to save the lesser races, twice.I mean yeah I love Odahviing, real kick ass dragon to have around. But he's a living, breathing contradiction of the "Oath" the Blades flaunt when it's convenient. That's why I don't take them seriously, among other reasons.