Just FYI: As with the templates, the same would apply to these HTML files that the structure could change at any time and we can't consider any of the variables we assign to the template part of API and keep BC.

When a template gets overwritten, I think keeping BC or staying update with changes should be a duty of the plugin author, the templates overwriter.

Let's do a practical example:

as plugin developer I would like to remove «custom» ranges from regular users selection, in order to avoid custom report calculations

            <div
                    id="comparePeriodToDropdown"
                    piwik-field
                    name="comparePeriodToDropdown"
                    uicontrol="select"
                    options="[{key: 'previousPeriod', value: 'Previous period'}, {key: 'previousYear', value: 'Previous year'}]"
                    ng-model="periodSelector.comparePeriodType"
                    full-width="true"
                    disabled="!periodSelector.isComparing"
            ></div>

I need to edit the array of options, removing the first item: {key: 'custom', value: 'Custom period'} in a conditional mode (by user's privileges).

Doing this goes deeper in the Matomo's UI, but, you know, you can already go deep using jQuery inside a plugin's javascript asset. As you can see, the last «custom» choice from the range list is already gone.
I need to remove the «custom report» from comparison. Angular components aren't reachable by jQuery.

Hello there, I want to inform you that my plugin upgrade path to 4.x-dev is blocked by this still opened issue.
In the past, we used jQuery to do the dirt stuff, but, since Angular introduction, jQuery got overridden.

@tassoman While I agree that solving this issue would be the right thing to do, I am not sure why your solution wouldn't work any more with Matomo 4. Nothing changed (Matomo used Angular and jQuery before) apart from updating the versions of a few of them. If you want to, I can take a look at how RerUserDates.js will continue to work.

The «compare to» select field is populated on rendering, by an array of values can't be overridden anyway (I'm aware of)
ng-model="periodSelector.comparePeriodType"

BTW probably it won't help but maybe it's possible to hide certain options through CSS?

fyi @Findus23 with Angular being removed in 5.x-dev we can maybe close this one?

With vue it won't be easily possible to overwrite the templates for certain components as they are included in the vue files.
Will close this as won't fix.