To be honest, I'm not really for or against the addition of another tier, per se, but if there were a $50 tier, I would very likely fork out the extra $24.50 to move up to it. Scrap that. If there is a $50 tier created, I will move up to it.
That might seem selfish to some, but that the fact of the matter is, it's just giving that little bit more incentive to donate a reasonable amount of money - it's a good thing for the community IMO.
That said, I could certainly understand if the current Tier 6's are worried about losing the exclusivity of their rank and the other political issues that might arise. Just putting my thoughts out there.