SUMMARY You can see a 100% cpu ussage or notice that some process is requesting too much memory but when you try to see which process was doing it, it is already behaving normally. Why not have an historic of the most cpu, io or memory (select one of them) processes, just the name, pid and cpu, io or memory, just like you can have an historic of anonymous cpu, io or memory. One way of showing that information can be done with area graphics and the information in the hover tip.
I think this is worth considering. It's something I've wished for myself from time to time, when a particular app has short, high usage spikes.