The R in WRS stands for Rear. The WRS shifts the back, not the lens. Therefore it's a better camera for stitiching.
Yes and No.
The WDS rise / fall movement is applied on the front (i.e., lens side) of the body and its lateral shift movement is applied on the rear (sensor side) , whereas the WRS applies
both rise / fall and shift movements on the rear, which is a better solution for most purposes.
(FYI, the positions of the two movements can be effectively swapped front to back by rotating the WDS body via 90 degrees by using the tripod mounting hole in the wooden grip instead of the one in the L-bracket on its bottom.)
The WDS also has a greater range of rise / fall movement than the WRS 1200 you mention, although it's physically larger and heavier, too. The WDS is the older of the two bodies, so you will likely find it a bit more difficult to find any N.O.S. or used items should you want to purchase any accessories for it. (I don't know the production total, but in my experience, there appear to be more used WDS bodies available than WRS or RS series bodies. Also, if it matters any, most used WDS appear to be sold privately, whereas most used WRS and RS bodies are sold by dealers.)
IMO, the biggest difference between the two have to do with ergonomics -- the WRS models are noticeably easier to use, say, handheld, than the WDS -- and also price, because as it's easier to find an inexpensive, used WDS than any model of the WRS and RS series bodies.
You pays your money, etc.
