Feedback from users:

Now that we've made the data model of the build pipeline plugin pluggable,
it'd be nice if the build pipeline would allow make the rendering pluggable — the particular feedback was about showing the same card and arrow like UI but with a different skin (see ThoughtWorks Go Pipeline screenshot for the hint of what he was thinking about.)

This seems like a sensible feature as it'd allow other graphically-minded people to innovate.