The developers are working on a new version at the moment but, unfortunately, I do not know when it will be released.
In the meantime, I would certainly recommend upgrading to v1.7.3 as this version features significantly faster publishing times (especially for sites with a large number of galleries).
For example, I created a test site in Showkase v1.7.3 with 128 galleries.
The initial publishing of the site took approximately 60 seconds. Subsequent publishing took approximately 5 seconds.
Please note that if you change the theme or the value for 'Customize Theme -> Gallery Index Page -> Thumb percent height', then thumbnails will need to be recreated and the publishing time will increase but, as long as thumbnails do not need to be recreated, publishing will be noticeably quicker.
This is not a strict benchmark (and actual publishing times will depend on many factors such as your web server) but my own findings should hopeful give you an idea of what to expect.
Incidentally, the bug noted above was fixed in a recent update to the Showkase v1.7.3 zip file so if you update to v1.7.3 just now, you will not need to manually implement the bugfix.
The bugfix was just a single line change in a single file so only the build number changed (to "2018.03.29.09.24.33" for Showkase-Standard and "2018.03.29.09.24.34" for Showkase-Pro).