There are a few other files that can reasonably be pushed to Zookeeper, e.g. solr.xml, security.json, clusterprops.json. Who knows? Even <collection>/state.json for the brave.
This could reduce further the need for bouncing out to zkcli.
Assigning to myself just so I don't lose track, but I would love it if someone else wanted to take it...
I'm thinking the commands would be
bin/solr zk -putfile -z <ensemble> -p <zookeeper path> -f <local file path>
bin/solr zk -getfile -z <ensemble> -p <zookeeper path> -f <local file path>
but I'm not wedded to those, all suggestions welcome.