OK - let's try to break the ice on this forum.
I was struck the other day by the realisation that the world's most popular programming language is probably Excel, which can be seen as a kind of pure functional language. What's interesting about Excel is the extent to which it is usable and has seen mass adoption by people who aren't developers and don't think of themselves as programmers.
Modern trends like the one towards FP and especially ReactiveX are in turn taking conventional programming closer to the spreadsheet model.
Thus it seems a shame that spreadsheet theory has seen so little progress. There is Chorus which is a followon from Subtext. There are some interesting papers on converting SQL queries into spreadsheets, there is a lot of data about the error rate inside spreadsheets (don't look). There is a tutorial on how to build a simple 3D graphics engine in Excel (I am not kidding). And Excel can be used to build full blown GUIs on top of an underlying "backend" made of spreadsheets.
There's also Unreal Blueprints, which are an interesting form of visual programming, which combines a notion of temporal control flow with FP. My experience with that has been that it is still perceived as "programming" by users though and that tends to scare some people away.
Does anyone know of interesting research in this space? Are there any ideas that could produce some useful leap forward over Excel?