If you want to take a crack at a Titan/CQL3 interface, that would be generally useful even outside the Scylla conversation.
The Aurelius, now Datastax, team may have tried this and hit performance issues, can't remember if that is true or imagination at this point.
But sooner rather than later, moving Titan on Cassandra to CQL3 or at least off of Thrift will need to happen.
For example, Astyanax has stopped moving their Thrift support for Cassandra forward from what I can tell - stopped currently at 2.0.x.