Hi @daniel, good to hear from you 
Thanks for your input. Unfortunately we cannot implement your suggestion as the yellow and blue colors are standard for other things in our interface.
However, as you noticed we’re trying to leverage other visual tricks to make the interface more accessible. We recently reworked the contrast on the coverage indicators (the topic of your initial post!), or we try to pair colors with icons in other situations.
I can tell you that the User Experience team at SonarSource has made accessibility for partially sighted people one of its priorities for 2019 
So if you’re following our releases announcements you’re going to hear about this topic again soon!
We already have a backlog of things to improve, but if you notice other areas of improvements in the interface, feel free to ping us again in the future.