Biggest open issue for me: after I send code to the REPL the line becomes unresponsive for both editing and evaluating. Is there something taking a long time that it’s waiting for? This was the thing slowing me down the most yesterday.

It could be several things. We would need some more details to better guess, but maybe your evaluations took time, or they might have returned big chunks of data. Calva is not very smooth handing large data structures, unfortunately.