That's very true, but at least Paladins are all unified around a certain 'Light' theme. Obviously, the main difference are Taurens and I think it'd be incredibly awkward to see a Tauren paladin in a hall filled with Knights of the Silver Hand, but like I said at least there's a very distant connection of Light to unite them.
Priests are probably, in my opinion, the most difficult class to build any sort of common meeting place for them. They have very clear contrasting speccs within itself; Holy (including Discipline) and Shadow. Straight away, they're going to have to build a place that conjoins two rather oxymoronic ideologies.
That in itself might be a difficult task but not impossible. Nearly all the races have some sort of 'shadow' theme to go with; Draenei have the Naruu, Trolls are the easiest and their hall could be Loa centric, and Forsaken could literally just have a plagued Church. But then enters the race theme. I just really don't see how they're going to pull off a realistic take on our class that unites both the oxymoron ideologies of our specs AND the wildly different racial religions that allow them to be priests.
I almost think and hope that these class holds will be faction dependant. It would ease it a little, at least.