Interesting timing. The subway in San Francisco (BART) is just putting out their new stripped down map as well. We were the cartographers on the project. Your quote about data that keeps getting added over time (aka map creep) is something we encountered as well. We did keep the water on these since the 'Bay Area' revolves around water and bridges. See old and new here http://www.flickr.com/photos/juliegoetzen/2227400621/ and http://bart.gov/stations/index.aspx
The new London Tube map is out, and overall it’s a big improvement on the most recent versions. There’s been a thorough decluttering, removing a lot of the fiddly, little used detail which usually gets added because someone says “But we must include…” and no-one replies “Putting more and more on a piece of paper doesn’t mean you get more and more over to its readers”.
Here are the old and new versions (click on pictures for fuller versions):
Aside from the improvements, the new map has three issues:
(a) a smattering of typos / inconsistencies
(b) the disabled access information is still stuck in the worst of both worlds – extremely intrusive on the map design and yet also very incomplete in terms of the information you may actually need
(c) the Thames is no more
Yes, you can whizz over or under the Thames by Tube or bus without having to know where it is, but it is still a useful frame of reference for the map – and without the Thames the map takes a step back in 8providing integrated transport information for it means it’s less useful in giving information about the Thames riverboat services. Instead of having the blue line of the Thames to mark their route, you have to hop from station icon to station icon to work out where the route goes.