perfherder has continued to provide much value and continues to be a source of truth for many. AWSY has a lot of great data and is fully integrated into our sheriffing model from perfherder alerts. One concern that developers have is being able to easily diff the data between one revision and the next. There are some instructions in bug 1376105 comment 4, but those are a bit hacky- it would be great to do this automatic or in a much simpler manner. I see perfherder as being able to find a current artifact and a previous artifact- then there would be work to display the differences (probably taking about memory code and allowing it to support two revisions- or copying parts of it to build a viewer inside of perfherder. One other thought is perfherder could build a .json object with both artifacts and the end user will be prompted to download.
I filed a similar bug with respect to the new compiler warning measures. In general there seems to be a need/desire for custom tools to interpret the perfherder data in domain specific ways (ala the reftest analyzer), it would be great if we could provide support for this at an API level so that submitters could plug stuff in specific to their performance framework.