My view: When a clear majority of the local population wishes to secede, that they will provide protection for the rights of those who disagree and do not force them to leave, they have good motivations for leaving and that they are willing to be a peaceful member of the international community.
I would say that Kosovo fullfils between one and two of those conditions. And this is being generous.
I'd say three. Two is debatable.
And I'd say two (1st and 3rd). Three is debatable (4th).
I wonder how South Ossetia ranks on this scale. I would say 1st and 3rd, probably 4th.
Given that South Ossetia has never (in the modern era, anyhow) been a de facto part of an independent Georgia, I would consider it unrateable.