You could still do everything the way you are used to if you want, but you won't be taking advantage of as many improvements.  I actually think Poser would be far easier to learn now than it was then.  Things work more intuitively, so I still find myself doing stupid things out of habit which are no longer necessary.  I feel I am constantly un-learning old versions because Poser now works so much better in every area.  I can only begin to list the improvements over that time...  Firefly... morph brushes... area render... so many little things everywhere.