Can we do without ranks in Burrows Wheeler transform compression?

Compressors based on the Burrows Wheeler transform (1994) convert the transformed text into a string of (move-to-front) ranks. These ranks are then encoded with an Order-0 model, or a hierarchy of such models. Although these rank-based methods perform very well, we believe the transformation to MTF numbers blurs the distinction between individual symbols and is a possible cause of inefficiency. Instead of relying on symbol ranking, we examine the problem of directly encoding the symbols in the BWT text