Hopefully the replacement unit you receive will be less noisy, but all fans emit a certain level of noise. There is a PicoScope 5204 running on my desk at the moment and I can only just hear it, but to be fair we have a heating / ventilation system in the office which does produce some background nosie.
Both points 3 and 4 are on our "to do" list but other than saying they will arrive this year I can not give any firm dates.
Point 5 (XP hibernation) is something we are looking at. I have been told that there are several different hibernate modes for USB, some for example leave USB devices powered so they can wake up the PC others do not. We will make improvements in this area but have to ensure any changes work reliably across different operating systems, USB hubs etc etc.
Hope this helps.