One of the valuable bits of information that WoL provides is an ability to compare performance for entire raids. Do we really have the performance for this boss? Should it be an easy kill, or is it going to be hard? How are other groups performing in the same fight.
Back in the days of 10- and 25-mans, the summary page for each boss was a good source of this information. But now, the median DPS and HPS totals are nearly meaningless, because the raids other than Mythic aren't of known, fixed size. Is that 250K DPS coming from 17x15K DPSers in a 25-man, or is it 5x50K DPSers in a 10-man group?
I'd like to see the summaries show median numbers on an individual basis. That is, divide them by the number of people in each role, or at least by the size of the raid. Then I can work out for my 14- or 21-man raid whether or not we have an appropriate amount of DPS for that raid size.
The extra-effort stretch goal would be to provide the summary stats for different ranges of raid size. Most people agree that the scaling makes the fights easier with more people (just as the old 25-mans were easier, person for person, than the 10-mans). If so, successful levels of DPS for a 30-man might not quite be enough in a 10-man, and the only way to judge that is to look at the kill percentages and stats spectrums for different raid sizes, not averaging them all together into one display.
Other comments with respect to ilvl / stats would certainly be welcome, too. The rankings of individual players aren't currently useful for making this sort of comparison, because it's too time-consuming to try to hunt down the proper place in the scale for the gearing of your own raids. Summaries by brackets would be useful, or a couple of boxes to filter the list to make your own brackets.