When using the Activity Stream gadget there are currently only 4 filter options:
Project
JIRA Issue Key
Update Date
Username

It would be extremely useful to be able to filter any combination of categories or actions including resolution, Workflow Transitions, time logged, etc.

Another approach would be to allow users to create a search filter & then to stream either general or specific activity on tickets falling under that search filter.

Additionally, the constraint of Display Options > Limit to XX Items is overly rigid. Would be very useful to be able to constrain to a time period, ie. 8 hours, 1 week, etc. up to a configurable max number of items.

EX:
Activity stream showing every time a user in the CS Group transitioned a ticket from "Resolved" to "In QA" over the past 24 hours. Show 20 Results + link to full list.

EX:
Activity stream showing every time CurrentUser() commented a ticket forever. Show 5 results + link to full list.