Now obviously we know nothing about 2.0 but assuming they continue the color palette I'd love to see it simplified. Currently we have 8 total primary colors with 6 secondary colors. 2-3 of these are called maybe 2-3 times(ditch those) and more if possible.
It'd be so much easier for users/ style makers / add-on developers if they had something more unified:
textCtrlBackground / textCtrlText (the second you turn this dark it looks awful because the default has hard coded borders so you have to go into the property anyways)
dimmedTextColor / mutedTextColor I think we could do with just a single fainttextcolor
Currently I think primaryLighterStill is used for a lot of borders across the style, but used for other things as well which can cause issues if you change it. Be easiest if it was actually labelled like xfBorder1/2. Also would make it more universal for add-on developers too, I often see to many times add-on developers choosing a random color which might look good for there style but ends up causing a ton of manual fixes(this is no ones fault since there isn't a more defined labeling system on the color palette).
I think burning board has a system like this in place which I don't have access to at the moment, only tried out a beta version before but it seemed nice.
We also did a setup like this on our framework and it's made it so.... much easier to work with.
Last thing this is just more a general concept of my suggestion, not the exact setup I'd necessarily want. I'd leave that up to the XF Team