Wrong.

You will need to obtain the Victoria 4 figure anyway as the WM only adds to the base figure and doesn't replace it. Posing isn't easier it just looks better (in close ups and when clothing isn't used). For most things WM doesn't really make a big difference.

Version 5 is an attempt of Daz to include the WM features in their own product. Few consider it an improvement over version 4 when using Poser. Stick to Victoria 4 and Michael 4 for now and you'll be covered for most of needs.

Don't forget abouth the things already included in Poser. Any piece of clothing can be converted. Other things can be adapted to fit properly.