I've been following the discussion about replacing the ArcSDE command line tools by geoprocessing tools for a couple of years now, and I'm wondering whether I'm alone in being a bit sad about this? Yes, the new tools are nice, helpful, certainly a GOOD thing, but why throw out the command line versions? We have a couple of people who concentrate on installing servers - they go out to customer sites, set up a Linux server (or Windows), install Oracle, install ArcSDE, setup the GDB schema, all that. No ArcGIS for Desktop anywhere in sight (that guy comes round next week). Everything scriptable from the command line. Now or at least from 10.3 on, it looks like they will need a Windows machine and a Desktop installation and a license server and ... to accomplish this.
Geodatabase install hasn't been scriptable on Linux without ArcGIS Server (and ArcPy) for a long while now.
While I miss the simplicity and performance of API tools, I won't miss the complications to geodatabases caused by folks incorrectly using those tools.
I wouldn't recommend holding your breath until command-line tools return.