Update the value/cost analysis of tickets related to #14544, 2020 edition

We did the first session in January 2019. We want to update the list and the spreadsheet again 2-3 months after 4.0 → around January 2020

This time we should also:

Integrate new issues from 4.0 once the dust has settled a bit.
Identity tasks that are good for designer to work on (good value/cost and good implementation cost).
Gather some more tickets from elsewhere in the bugtracker (optionally).

Parent Task: #14544

Original created by @sajolida on 16997 (Redmine)

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