This makes it harder to distinguish between hovered buttons, despite the recent changes in the direction of making it easier to distinguish.
This also creates problems with readability such as this:
[media][media]
Pre-1
[media]Pre-2
[media]Related issues
Attachments
Comments

[media][media][media][media]
Is the fact that text is now less readable on sliders intended as well? I would consider that an accessibility issue.