It would be really sweet if, when you interact with one chart, it applies the same effect (to the timeline) to all of them. Is that even doable with the highcharts components, that you know of? Further, would anyone else agree that it would be a nice behavior?
One ring to rule them all 
I think it will be a nice feature. What will be really awesome if we can capture server cpu/memory and project it in reports.
That is needed, but beyond the scope of Gatling.
But maybe it could be implemented by having a configuration option that says “here is the graphite server that has the data, go get it and integrate it” - But I have a feeling there are much more important features on the roadmap.