James,
I kind of like it the way you have it now. I was always a little confused about the overlap in some of the categories but these 7 seem fairly good.
Workshops/seminars could also include announcements or events and the such. Maybe a title is “Calendar of Events” or just “Events”. It’s a place to tell of or set up outings of all sorts.
I think the Critique and Business forums should stay as is. But then again, I am always looking for Critiques, so if the critique forum were to disappear I wouldn’t miss it.
I am still confused on the benefit of Professional vs Open forum breaks, especially when it comes to Critique.

I like the differentiation of National parks from Nature/wildlife. I think the National Parks theme is a differentiation you created from the start. I think omitting outside of national parks in lue of Nature/wildlife is a good move.
Again Nature/wildlife good as is General for a catch all.
But as I reread David’s suggestion I wonder. Now I am up in the air:)
Pet Photography I like. I agree that the majority of the conversations revolve around the pros, but the majority are also general discussions. If there is a Business type thread with specifics it could go up in the Business forum. Like when Julie asked about the Price lists, she went to the business forum. But if a more generalized thread evolves into more of a business nature, why not keep it in the pet forum.

Are you going to migrate all the posts that were removed into the remaining boards?

Just thinking out loud,