Having been working with PT a bit more recently, this is one feature that seems simple but makes things a lot easier in terms of visibility:
Basically, the area underneath the automation line is darkened; with a lot of tracks this really helps with quickly reading what’s happening on each track.
Not one of those ‘the lack of this feature stops me from working!’ situations, but certainly useful.
Oh, and while you’re at it; anti-aliasing of the automation lines/curves and sample waveforms would be grand too! (already on the mac it seems, but not on the PC).