uMap, a poor GIS viewer? Hummm…
OK.
The target user is not a “GIS user”, just somebody in a organisation who want to access Tryton models via a map, with associated shapes (as associated notes, or associated comments).
From there, each project will have a base to do whatever it wants with geospatialization of Tryton’s data, including to interface with existing GIS software.
That does not mean we must implemented because someone wants something. There should be a valid reason to have such requirements.
You’re right Cédric: just because a customer asks for a fonctionnality doesn’t mean the customer himself and others need it 
… and therefore, that’s not a good enough reason to work on integrating this feature into Tryton’s core. OK.
I thought that a cartographic view of Tryton objects, begining with Parties, was a universal need applicable and useful in industry (here agricultural, as part of our customer request). But I understand that it must be deported outside by an application that do the job.
Anyway. Admit that it’s hard to resist integrating features that would allow the customer to be productive in Tryton, and the map view, like the list view, allows to process data faster.
My two cents…
Well I can not see any useful application for such limited feature (it will never be like a GIS).
For me it looks like using the calendar view for a calendar application, it does not work because it is not as good as a dedicated calendar application.
It is difficult to understand how this could be an improvement without concrete use case.
Yes but not all data. And how I see it, this will be a dedicated client. I would not even try to integrate it into the current client. As an example @ced already talked about a calendar integration.
For a customer I created a dedicated webapp which displays a planning board. Users can use the Tryton login and the data comes and goes directly through the Tryton API with JSON-RPC. The board is dedicated to visualize the planning, but the user is still able to use the default client to add new planning items or make changes.
I also made a proof-of-concept with Leaflet to show the planning items on a map based on the party location.
Looking at agriculture, there are lots of things going on in that sector. Everything moves to precision farming with GPS. Tasks are generated ‘offline’ and loaded into the equipment. The equipment generates data on how well the crop grew. Based on that information the farmer knows where the fertilizer should go next time and create a new task for that etc etc etc. I would create a dedicated client for this and the ‘side’ data can also be managed by the default client.
BTW productive in Tryton IMO doesn’t mean using the default client. Using Chronos will allow you to more easily add your hours, which is more productive right?