I can sympathize with you on DL handing out MQM's like candy on Halloween. But adding another tier isn't the solution. That would just end up looking like the whole boarding zone fiasco where everyone has a special zone, and the zones really don't end being that special.

The elite levels are fine, just stop with the huge MQM bonuses through AMEX transfers and/or signup bonuses. MQM's for meeting large min spend are okay in my book, since they require a significant commitment to reach them. Rollovers are fine in my book too, as they don't usually affect status long term. A large rollover from a plat might get them to DM the next year, but if their travel stays the same then they'll drop back down the followoing year. Perhaps limiting DM rollovers to ~50k might help prevent people from securing DM for years and years, even if they stopped flying.

In short, the problem isn't the elite tiers. Just fix the MQM earning sources.