Improved filter/cross-filter functionality and formatting options for line charts

Currently if you filter a line chart from the legend it de-emphasises the unfiltered series by adding transparency (good); brings the filtered series to the foreground (good); but adds data markers which can really detract from the visual or even worse, completely obscure the trends if there are lots of points (bad).

I would like the option to choose formatting when line charts are filtered...including an option to set a default colour (likely light grey) for all unfiltered series, in order to really highlight the filtered one(s).

I'd also like this to work with crossfiltering. Currently you can't cross-filter a line chart from another visual as per related idea at https://ideas.powerbi.com/forums/265200-power-bi-ideas/suggestions/32540377-line-charts-should-allow-cross-filtering-to-other

But this results in inconsistencies with other visuals, and means we may be forced to retain the legend in a line graph when we don't want to. (I often use a bar chart as a legend for other visuals that CAN be crossfiltered, as outlined here: https://twitter.com/InsightsMachine/status/1218638496664936453

Here's a twitter thread on this with images: https://twitter.com/InsightsMachine/status/1219021672742735878