I am posting here first time, so please excuse me if this is not right place to send something like this.
Please check - http://stackoverflow.com/questions/6091306/can-i-make-git-print-x-y-z-style-tag-names-in-a-sensible-order
And also - https://github.com/gitlabhq/gitlabhq/issues/4565
IMHO "git tag" is expected to show tag-list ordered by versions.
It may be case, that people do not follow same version numbering convention. Most people after x.9.x increment major version (that is why they may not be affected because of this)
Another option like "git tag --date-asc" can be added which will print tags by creation date. (As long as people do not create backdated tag, this will work).
Thanks,
-Rahul