If your 'pedestal' museums are the equivalent of statue gardens for non-statues then I like the ideas, in fact why not fold the statue garden into the museum as just one of the many things that museums can hold, flexible and simple at the same time.
The number one building that I'm missing right now is the temple or some kind of area ware religious practices take place, Dwarfs are depicted as very religious in fantasy literature and would have multiple temples to a Pantheon of gods within their forts. Making temples and dedicating them to various deities (and assigning some priests) would be very fun. I could see the fort as a whole demanding these temples the way that nobles demand stuff.
Regarding statue gardens and "museums", I was thinking the same thing, really.
But as far as religion goes, keep in mind that dwarves do vary at least a LITTLE between different works, and that we really have no idea how DF-style dwarves treat religion.
All we know is that a civilization has a given pantheon and that dwarves worship their own chosen patron deities to their own degree of fervor. The rest, we have no clue yet, as far as I know.
I can see dwarves being a tad ambivalent about religion, actually. As in, it doesn't affect their civilization as a whole very much (e.g. they don't get as uptight on a grand scale as elves), and religiosity isn't really expected of the individual in their culture, religion being treated as sort of a personal matter, with dwarves having varying level of devotion to varying gods, generally representing things they can relate to or consider important. So I can see temples and such going into the game, but not as an incredibly important thing, especially when you consider that most dwarves in a fortress won't worship the same deity.
That being said, I do think temples and religion could be incorporated more heavily into the main game, and all of that is just my own interpretation, which may differ from anyone else's, including Toady's.