As London Reconnections notes, the map is accompanied by very little explanation, either to the likelihood of these plans ever moving forward or the costs involved. The map therefore offers a juicy platter for speculation.
The most unexpected feature is an extension westwards to Victoria and Euston/St Pancras, two of the busiest transport hubs in the capital. The northern termini are not only home to Eurostar and HS1 services, but will also support the proposed High Speed 2 line to the north of England. A DLR hook-up would ease the burden on the Northern Line, offering an alternative route into the City and Docklands. The Victoria link, meanwhile, could make use of disused Jubilee platforms at Charing Cross, cutting construction costs.
The proposals also see a long-anticipated extension east to Dagenham, a double-tracking between Bow and Stratford, and a southern extension to Catford and Forest Hill.
London Reconnections has expert analysis (and a good comments thread) of the proposals, which would render the 'Docklands' Light Railway something of a misnomer.
Update: 853 blog has a response, asking where the link to Eltham is.