I work for a company that has many locations with poor bandwidth. Connectivity is sometimes intermittent.

I have worked around this issue in the past using the technique described at https://yetanothersharepointblog.wordpress.com/2014/04/09/rendering-json-from-an-xsltlistviewwebpart/. While it is 'kludgy' the way I had to to it, ,the results were fantastic. I suggest that SPFX embrace this technique to deliver a webparts initial data when the page containing the webpart is initially rendered.

I envision a that in the sharepoint UI when a user edits a webpart, on the toolpane there would be a button called 'data' or something below the existing 'Configure' button. Clicking that 'data' button would let the user enter a bunch of key-value-pairs. The key would be the name of the 'data set', the value would be a query (CAML or rest, I don't know) that would define the data to be retrieved.

The framework would execute the query as the page containing the webpart was loaded and format the results as JSON. The json results would then be made available to the spfx webpart as and nested objacts of an 'context.InitialData' object.

In addition to the fantastic performance gains for remote users, this could eliminate all data retrival code from a whole class of webparts saving developer a lot of time. It would also make webparts developed with this feature way more configurable to adapt to a changing environment.