There are several UI enhancements that would be worth to have in ultra.

For instance, many existing PRs done by @parttimenerd are basic stuffs that we really need to have in Firefox Profiler to make it usable:

• Implement Method Table view #4227 : This one provides a method table view that is quite common in profiler and would help to investigate issues for a particular method. Today, it's not possible to have such information, which is quite frustrating.
• Add sort buttons (▲/▼) to TreeView columns #4265 especially interesting for markers with a duration (e.g. JitCompile or GCEvent in ultra)
• Implement marker based stack strategies #4293

Additionally, there are several other enhancements that I'm looking for:

• Styling markers: today, marker styles are hardcoded in such a way that I have to hack around and use an existing marker name in order to display markers in different colors and positions. We should be able to provide our own style as part of the marker schema.
• Show aggregate duration for markers: If a marker has a duration, it is interesting for a range to show the aggregate duration of markers. It could be shown when we select a row in the marker chart and marker table (when filtering)
• Custom counters track: Counter tracks are also hardcoded to only the supported following category Memory, power, Bandwidth. This is very limiting. For example, I would like to display the memory for each GC generation but it seems that cannot achieve this with existing counter tracks.