1:3 was perfectly fine. Look at TPG Valuations, various "what are * points worth" on these forums over the last several years, etc - all are right in that ballpark.
SPG has under-earned relative to redemption, and made it up in MAGC, PLT amenity, etc., for many years. Look at any "how many nights to earn a free night' analyses, then see how that changes when these other points are factored in. They just approached it differently. MR had better base earning, SPG made it up with bonuses, elite membership specials, etc.
I fail to see how a 250/nt SPG promo is terrible and 750/nt MR is OK when the 1:3 ratio is a fact.