It's nice that Lifetime Gold become Lifetime Platinum in the new program, while Lifetime Platinum become Lifetime Platinum Premier. Fair!
And SPG Lifetime Gold becomes Lifetime Gold (matching their lower Gold requirements) and SPG Lifetime Platinum becomes Lifetime Platinum -- which again is fair since they generally stayed as many nights as a Marriott Lifetime Gold member.
But they fact that they have two tiers starting with Platinum.. come on.. that's a tongue twister.