(Pixelmator Pro 1.2, Pixelmator Pro Beta 1.2.1)
(This is probably going to head in the direction of too much effort for too little benefit but I thought I'd ask anyway.)
I really like the colour accents on sliders but have noticed that they appear on sliders that are of a zero/max type but not on those that are of a negative/zero/positive type. Would it be possible for a slider that has a zero value in the centre to have a colour accent that starts at the centre? Mockup below. I have no idea if you're using Apple's sliders out of the box or creating your own so this may be something out of your control (pun unintentional).
What features would you like to see in Pixelmator Pro?