Irving - thanks for the response.  I appreciate the insight.   A few follow-up questions if you have the time:

So is it relatively safe to assume that if no content is being lost and duplicate content is being eliminated, then consolidation of URL's (pages) is smart?  Even if this results in the number of indexed pages dropping from 15,000 to 3,000?

This consolidation should conserve link juice and help make the category & sub-category pages much stronger correct?

Good point on the host crowding - all of the pages I'm looking at consolidating are deep in the site and really just product pages that are filtered very granularily, so they aren't high in the SERPS.

I'm considering making a change to using AJAX filtered navigation on my e-commerce site.  If I do this, the user experience will be significantly improved but the number of pages that Google finds on my site will go down significantly (in the 10,000's).

It feels to me like our filtered navigation has grown out of control and we spend too much time worrying about the url structure of it - in some ways it's paralyzing us.  I'd like to be able to focus on pages that matter (explicit Category and Sub-Category) pages and then just let ajax take care of filtering products below these levels.

For customer usability this is smart.  From the perspective of manageable code and long term design this also seems very smart -we can't continue to worry so much about filtered navigation.

My concern is that losing so many indexed pages will have a large negative effect (however, we will reduce duplicate content and be able provide much better category and sub-category pages).

We probably should have thought about this a year ago before Google indexed everything :-).  Does anybody have any experience with this or insight on what to do?

Thanks,

-Jason