Depends on the class/spec… there are a few where the distribution of choices is fairly even.
Others they haven’t done a good job with balance… like Druid night fey for example xD
This next coming patch they have attempted to balance the covenant more or each class. At first glance, it definitely seems like an improvement. Some class/specs better than others… for example, resto shaman is extremely even now, you can really choose any covenant.