I cant verify this, because I think Kane said it while answering a question about the new taming stuff, but I believe old school pets are in a different category when it comes to the new tier stuff.
I might be wrong; It was something I thought I saw Kane say, in world chat.
What I do know is that all mobiles have this tier system built into them, now. Which means they all have a chance to get a Teir trait-- especially the MoB's that have respawned since the patches addition-- which is possibly why the Greater Dragon, Gen 6, got the tier ability. Can the Greater Dragon Benefit from it? I don't think so, because I think the idea is to allow all of us to have an equal playing field with this teir system. We are all at square one perhaps. But that's was my impression, so I don't know... I'm assuming again.
I also know that there is more to come with this addition; and I place my faith in Kane.
He isn't dull, why would he knowingly add the bonuses when he knows us min/maxers will boost our pets to full?
This is his baby, he has spent a ton of time on it, he must have thought about this overlap. But if he hasn't good catch I guess. But my money is still on Kane.
That's all I have to say on that for now.
--Sturger--