1. Your manager and/or customer can't see your work unless they have a license and can understand the language. Mine only needs a web browser.
2. If the analysis changes, the documentation must be updated as well. Mine does everything on the same web page.
As for the questions, those are all ones that I have asked myself about several times and here is where I am now.
(1) It is not open source and you really are kinda locked into using the system once you get going. I really couldn't find a way around this as the real appeal for most engineers is the absence of the need to code stuff. I have documentation that describes how I solve most algorithms and some demos.
(2) Scraping web pages is high on my to do list. You can paste most forms of data already, but you can't yet import files directly. Seeing that this is high on someone else's list I may put most of my effort there.
(3) Right now, everything is done locally in javascript but there is no way to save changes without server access. Part of my business plan is to use a server side code to solve large data sets and possibly charge for that. I have been surprised at how well the browser has handled most problems though.
(4) The main problem that this will solve for most people is this ... You get data from a test run somewhere. You put that data on a server, run a Matlab or Python code on it and then create a word document to pass on that info. With my system, you upload the info, analyze it, and display the results all on the same web page. It isn't just about analyzing the data, it's about doing everything on the same platform.
(5) The plotting functions are pretty easy to use and you can get something up in a few seconds. I also have 3D plotting.