Credibility: On the topic of credibility, one thing people have asked for time and again was simply a listing of the major adjustments that have been made to the data. Every time I see Vgchartz mentioned and examined, that was the most major complaint which was easily addressable.
For the sales numbers, I think like other people have said; there should be a set time that they all go up at once. Say for example every Friday is hardware and every Sunday is software, that way people don't miss the updates. Recently the sales numbers have been even more erratic than they used to be, it would be nice to know ahead of time if the sales numbers will be late. I've seen cases where they haven't even gone up for one week and an official explanation would do wonders for dispelling the uncertainty.
I would also love for the information and sales graphs to be postable into the forums. We can't easily discuss a trend in the HW/Launch or HW/Date graphs if they can't be posted into the forums themselves. If you want more serious sales discussions we need more serious tools. Its the sites strength and we need to make better use of it.