The main features of CafeOBJ that are missing from CASL include built-in support for hidden algebra, behavioural equivalence, and rewriting logic, as well as indications of import and parameter modes.
Recalling that CASL is intended as the basis for extensions and restrictions, one might consider providing an extension of CASL including these features. A combination of extension and restriction of CASL would be needed to provide a language in the CASL family with exactly the features of CafeOBJ.