The Northwest promo is not diluting the elite program, in that the bonus miles will not count for status. It certainly will help along the trend of mileage inflation, which in turn will mean Northwest will raise award requirements. That seems a general, and perhaps very natural trend over the life cycle of promotional programs such as ff miles. It will ultimately lead to their demise.

Hilton is obviously using their elite level to promote new membership. Yes, that will dilute it. Ini my mind it's already pretty easy to get, and they have all these gold members chasing a limited number of room upgrades. If they want to have even more, that's their business. They have to weigh the costs vs. the benefits.