I agree. And I think the notion of the Galaxy class as being an "elusive" design went out the window with DS9. Roddenberry's original concept was that they were so big that Starfleet would have only a handful of them in service and during TNG that was the case. Once DS9 came around it turns out there were in fact lots of them. My feeling is that they had been slated for massive production and would end up becoming the workhorse/backbone of Starfleet as an eventual replacement for the excelsior design. I can imagine that 50 years in the future Starfleet is full of aging galaxy class ships.
Regarding the Ambassador class I think that if the model had survived to CGI we would have seen many more of them in DS9 but its another example of how real life effected star trek history the class remains one that "appeared" to be produced in only limited numbers which is a pity as I do rather like the design.