hmmm, i think you may be right. Although the 20% remains significant as "big money" will pay a slightly higher rate and that ultimately is the market mover in the ETF's that own MLP's and are subjected to that increase in a larger manner.
Most of us will pay the piper when we sell units and not before.
There was no reason to "change" the MLP tax status. Little to gain in the short run and MLPs actually generate more taxes when sold because the recapture is at ordinary income rates and not dividend. THe 35% rate on the ETFs is why they do not go up as much when the market goes up. Partnerships and C corps continue and will continue to exist in the future.