The difference between naming the categories in ATP and WTA is huge, and many prefer the way it's done by the Association of Tennis Professionals rather than the Women's Tennis Association.
Tournament names such as 'Premier Mandatory', 'Premier 5' and 'Premier' may be really misleading and it might be difficult to see the difference between these names. On the other hand, the ATP has a clear system with ATP 1000, ATP 500, ATP 250.
The same should now happen also with WTA tournament categories. Then Premier Mandatory and Premier 5 tournaments should be now 1000s, Premier tournaments should be under 500s and International tournaments will be 250s.