I can't speak for ryanmarsh, but I have a few thoughts.
* Excel really has two major ways of performing computations on data - formulas within the grid and actions upon the grid. Despite the utility of the formula based dataflow model, there are too many operations that have to be performed as one-shot operations via commands (or scripted via VBA). Having formula based approaches for sorting, dividing into bins, etc. would be very useful.
* It'd be nice if Excel cells could contain values other than scalars. (Arrays, tuples, lists, maps, matrices, complex numbers, etc.)
* VBA can be used to define custom functions, but there's a lot of marshalling overhead going to VBA and the programming model is slightly different. It'd be nice to fix both of those issues.
* There's no way to locally bind names within a cell formula, so often subexpressions have to be duplicated. (And I believe they're doubly evaluated too.)
Shameless plug: I'm a founder of Alphasheets, a company seeking to solve problems like these! I couldn't resist replying after seeing these comments.
We make a collaborative (Google Sheets style) spreadsheet with Python and R running in the sheet. You can define functions, plot using ggplot, embed numpy dataframes, matrices and all that good stuff. We don't let people use macros, all the code runs in cells because we think macros are too brittle. You can check out the website at http://alphasheets.com .
We're seeing that many enterprises (for example, in finance) that have Excel power users are moving to Python because of limitations like these, and are running into adoption issues because people like spreadsheets so much. That's generally where we come in and provide a bridge from the Excel world to Python through a more friendly frontend.
We're also seeing that Alphasheets can help a lot with shortening feedback cycles on more sophisticated data analyses- Excel is the most popular self-serve analytics tool out there, but doesn't cover cases where you need Python/R/fresh data.
This is very nice. Problem is, there are sooo many more features in Excel you'll have to copy to get me to move. If you ask "which ones" I'll say "all of them". I'm a power user. I build huge dashboards and analytical tools in Excel. The thing I hate most is that all my work goes into a file that I have to pray works on the other persons computer.
The product is great. But you guys will need to launch a fully feature rich desktop client, which can sync with the cloud.
Else its the same thing mentioned in the previous comments. You would build a web app with 5% the features of excel, and the moment somebody reaches use case that can't be solved with your tool, they will have to switch to excel. If they have switch every second time they use your product. They might as well do all their work in Excel to begin with.
You have to be feature compliant with excel and you can't do that on a web app alone.
* see a modern replacement for VBA, dare I say using JS
* be able to share a document that won't break when someone opens it on their computer (even if its using all the excel bells and whistles including external data sources and plugins). Google Sheets by contrast, is just a link.
* be able to use all the amazing features via the web and/or an app
* Excel really has two major ways of performing computations on data - formulas within the grid and actions upon the grid. Despite the utility of the formula based dataflow model, there are too many operations that have to be performed as one-shot operations via commands (or scripted via VBA). Having formula based approaches for sorting, dividing into bins, etc. would be very useful.
* It'd be nice if Excel cells could contain values other than scalars. (Arrays, tuples, lists, maps, matrices, complex numbers, etc.)
* VBA can be used to define custom functions, but there's a lot of marshalling overhead going to VBA and the programming model is slightly different. It'd be nice to fix both of those issues.
* There's no way to locally bind names within a cell formula, so often subexpressions have to be duplicated. (And I believe they're doubly evaluated too.)