Comment 16 for bug 179452

According to the bug triage project wiki page, "Only use Critical priority for extremely serious bugs that will be affecting most everyone using Inkscape. ".
Since Export to OCAL is not a released feature, and is only available on Linux, we can't say it's affecting everyone.
And it doesn't lead to a crash or data loss, nor is a fundamental feature.
Let's change it to medium and postpone again.