Excellent thread and some excellent ideas. I love the lumber camp for Isengard. It could be built where there's a wood resource, creating wealth but giving an order negative.
Maybe there could be a bit of a "class" building in Gondor? You could build a "men of the West" building whic gives negatives to growth but maybe a unit experience bonus and a better chance of good ancillaries, and a Men of the Dales building giving a pop growth bonus but a stat negative and maybe some kind of a building tree limit (maybe they are less educated and interested in Numenorean high culture).
For some reason I think the axemen of Lossanarch should be linked to the Men of the Dales but there's no lore basis for this. It just feels like less of a Numenorean unit to me, but thats just me.
Dwarves curerently have alcohol related culture buildings, but maybe they should be craft related? Perhaps forges/armourers could double as culture as well as upgrade budings?
Thinking on the fly, I'd suggest to simulate the dwarves apparent preference for mountains maybe they could have a "craft workshop" to give culture bonuses and attack bonuuses but they can only built in mountain provinces (perhaps places with mines? or certain mineral resources?).
Also Balin (IIRC) mentions to Bilbo that men send their sons to apprentice with the dwarves, so could there be some sort of apprenticeship building or guild for the dwarves?
In the sub mod forum there's an interesting unique building thread too: miost of my ideas seem to be there already eg Tomb of Thorin.
IIRC in TT Faramir says that the standing silence before meals is about the only formal degree of honour accorded to the Valar, so a shrine to the Valar is a bit non-lore IMHO.