I have also seen the route rated as low as 5.4, and most of it is that or less, but there are a couple short sections that are technically harder than that, although those sections are short, such as the last section of wide crack at the top of the Grand or Giant Staircase. Here is my East Face <a href="http://bearbnz.net/rock_climbing/Whitney/east_face_topo_2.jpg">topo</a>, and as has been traditional most of the time, the rating reflects the hardest individual move. This is, of course, in my own biased opinion, staked on my status as a perennial softman climber. Some climbs have a cumulative rating harder than any individual move if the climbing is sustained at that (lower) grade.