Most R lenses come in different versions, the Elmarit-R 35mm comes in 3 versions, mine is the second version and if feels quite stiff, partly due to design and partly due to old grease. Later (last) versions, like my Summicron-R 50mm from 1981, are very smooth.

Re R4 sticky DOF lever: http://www.nemeng.com/leica/014c.shtml