I'd like to be able to specify which fields should be displayed when
viewing contacts as address cards.

I really like the look of that versus the phone list (which you CAN
customize), but it's really annoying to see things like street addresses; I
don't ever care about those showing there, plus I keep my cards set wide
enough for phone numbers to fit, but skinny enough that pretty much nothing
else does.

Being able to tell it specifically which fields to show (in my case, just
names, email addresses, and home/business/mobile phone numbers) would save
a LOT of screen real estate for me.