yep, architecture is best on FF if you can afford TS/PC lenses otherwise there isn't a big difference. Wide angle lenses for cropped cameras used to be rare, and have very bad distortion. Now there are far more ultra wide angle options for crop than FF and distortion is similar.
High resolution work is also a FF advantage, but only if good technique is used is it really a necessity. E.g. You could have a 24MP D71000, use excellent glass, shoot at optimal apertures, use hyper focal focusing, mirror lockup, remote and a sturdy tripod and get far more detail than picking up a FF camera and using mediocre lenses combined with slopping technique and hand holding. Of course the same bad technique with a high res crop will be worse still, my point is if you are not doing everything right on crop then there is no need to move to FF, yet.
You basically only really gain 1 stop high ISO performance and 1 stop shallower DoF - unless you are shooting wide open on fast glass then there is not real advantage. Shoot the sigma 25mm f/1.4 @1.4 on FF - you can't ever replicate that on crop. Shooting a 24-105mm f/4.0, buy some primes!