You can already do this without the IDE by adding a secondary controller to your Z wave network and downloading the Z wave firmware that way. (This option is not available for zigbee because you can only have one controller on visiting at work when using the profiles smartthings uses.)
Anyway, people have done that in the past for some required updates, including for Leviton and homeseer light switches.
So you have to get an additional device, you have to figure out how to add that to your network, you have to get the files from the device manufacturer, but if you do all that, then the individual customer can update their own zwave devices. And it is over the air updates.
This is the device:
And here’s a discussion of using it with smartthings. I know @HalD has done so in the past, but I don’t know if it works currently.