Smarter IDE folding, in effect? I'm always wondering what higher-level views of program flow we could have. Various tools have experimented with generating graphs and flow charts from code, or visual programming systems with nodes, but I don't know of any that smoothly blend between those views in the IDE?
I'd bet that it needs a better abstraction like LSP. IDEs are super expensive to build, so an IDE company isn't going to try to abstract away their business, so it's a long time between LSP-like developments, and I can imagine something that would enable that sort of thing needing to be a couple major breaking versions of LSP away from where we are, at minimum, which would mean a decade or two from existing across the ecosystem, at the least.