I agree about the scenery but I thought the Hawes side was harder! What really gets me from that side is that you can see exactly what is coming and know that it just gets harder and harder as you get more tired!
It's certainly harder psychologically from the Hawes side for the combination of reasons you cite; and it's less scenic, arguably. Going in that direction, you miss admiring Langstrothdale due to focusing on not crashing into the walls or the remarkably pretty river!
We've done it together twice; once in each direction. The northwards direction then led to the hard side of the Coal Road and the hard side of White Shaw Moss, each of which is harder than the climb before it ..... One of my more challenging forum rides, that one :-)
Regarding Park Rash and Coverdale, the cunning plan is to go up Coverdale and down Park Rash. It's the same argument as Fleet Moss really: Coverdale's lovely and you get to admire it on the way up. In this case, however, it's also an *awful* lot easier than going *up* Park Rash.