They do explain how a couple of undergrads were able to use the data to create something meaningful in the original release article but that specific site can definitely use a UX designer, or two.
http://opendata.cern.ch/search?ln=en&p=Run2011A+AND+collecti...
Not arguing the value of accessibility but in this case it's a nice to have rather than an essential.
I'm not saying it couldn't be better.
"Physicists must sift through the 30 petabytes or so of data produced annually to determine if the collisions have thrown up any interesting physics.
…
The Data Centre processes about one petabyte of data every day - the equivalent of around 210,000 DVDs. The centre hosts 11,000 servers with 100,000 processor cores. Some 6000 changes in the database are performed every second. The Grid runs more than two million jobs per day. At peak rates, 10 gigabytes of data may be transferred from its servers every second."
Yeah, I don't think it's feasible to release data that can be used to do deep physics.