While I don’t think the recent removal of the width settings are addressed there, they are in the change logs. In short, Apple wants everyone on this new cursor, which has very little by way of customisation at the development level. During this transition period you will see older programs using the old cursor—it won’t crash them out if they use it, but it is unsupported from this point onward and you will start seeing it everywhere (except maybe in some tools that don’t use Apple’s development frameworks heavily, like MS Word, which is another universe inside of the overall window frame).
Colour on the other hand, should be working. I’m not sure why you can’t change the colour of it in the main editor. I just did that a few minutes ago when testing something. Maybe you have revision mode turned on? That will override the colour to the current revision level (and always has). Otherwise make sure the preferences pane is active when you’re changing the colour. If you switch back to the editor to see what you’re doing, it disconnects the colour palette. A little trick there is to make the editor active, then hold down the Command key and click on the insertion point colour control, which is a way of sending clicks to background windows without making them active. Now you can freely use the popup colour palette while observing the changes.
Perhaps it is something involving the overall system Appearance setting? Try playing with different accent and highlight colours, and see if changing one of those makes a difference. My settings are grey accents and highlights.