Tons of features are disabled for Everything Gantt view. Can't change scale, for example (Month, Quarter, Year). You also lose most customization, other than filtering. Can't change color coding, options for displaying tags, etc.
Having these available would be great, but MORE ideally, I'd like to see a standalone Gantt feature, like how Dashboards can exist outside of a given Space. If we could create a Gantt chart, then in its settings, select lists/spaces to include, it'd expect it to have the standard "Space-level" options, while also limiting the amount of tasks is processing, to improve performance...since...everything view is understandably crazy slow.
I'd also love the ability to "start view" At a certain level of depth, being already opened. For example, Everything is always spaces, collapsed. If in those spaces, we are using the Gantt view to review content in 10 specific folders, I'd like to just have spaces opened by default OR don't even show them, and just show the list of 10 folders, that we can then expand.