Colours in field list
The field list should have some colour - the current design is very hard to see what are dimension fields and what are measures, and a simple addition of some colour, as used everywhere else in MS BI, would make this much better
webdav - folder browsing
Being able to browse to the report server from Excel (and other tools) through the file open dialog (or indeed windows explorer) through webDAV would extend the usability of the Report server massively
Publish the default visuals as open source custom visuals
A lot of (reasonably) basic settings on the default charts are missing - for instance gridlines across the chart area for x-axes the way y-axes can be enabled. Instead of trying to support each and every version of this scenerio, publish and maintain each of the default chart types on GitHub so ...
css minify, compression, and any more performance improvements
A quick audit in Chrome 66 pulls out a trove of places that could be heavily improved to improve performance. Minify the Javascript, minify the CSS, enable text compression on the web server, tree shaking on the CSS to remove unused CSS rules. The first 3 of those should be relatively trivial, a...
Measure picker
It would be really useful to have a dropdown on a published report to allow a user to pick a measure for a chart / to filter slicers, etc. We can emulate this by having a measure picker dimension, and a measure that uses a switch statement to pick a measure based on a user selection, but this ha...