Netscaler Knowledgebase

Version 9.0 would allow some traffic prioritization. Basically would have to limit traffic to the lower priority websites and put no limits on the higher priority websites. There is some traffic prioritization you can do on a per site basis, so if the majority of the traffic to a single website originates from a set of IP's you can give those IP's a higher priority than other IP's.

As for Traffic Analysis, you can do quite a bit. Out of the box you can do reporting on bandwidth etc. Also with Platinum  you can install Edgesight would lets you report on how long it took from a user to click a link for the page to load. It gives response times of the server, how long it took the server to process the request, how long it took for the user to render the request etc.