My biggest gripe with stuff that's not 2019 model year brand new on the $7000+ bikes is the fact that you still get some somewhat ugly cable management even with integrated bars.
I really want the 2019 headsets and stems that route the cables around the stem with a little cover over the stem and steerer area to get the cables cleanly back.
I'm not seeing much beyond Kickstarter stuff right now, or brand new items only compatible with a 2019 frame.