squinky:

The problem I have with it is that all the heavy lifting is done now by extremely sophisticated enzymes (proteins) that perform functions nearly impossible to imagine how catalytic RNA could do ...

Yes, that is true, if you want them to do as good a job as is done today. However, if you have an environment in which running reactions very slowly does not mean you get eaten before you can grow up, you can get by on catalytic systems that have very much lower efficiency and specificity. You will grow very slowly, and take a long time to collect the molecules you need to replicate, but as long as your neighbors are in the same situation, what's time to a molecule? Also remember that it need not be pure RNA. T-RNA manipulates an amino acid. Various other RNA and amino acid hybrids could have been doing some of the work that is now done better by proteins. It is exciting to see this kind of new knowledge coming so fast, now.