It's been a while since we heard any buzz about the new DotA map but recently IceFrog shed some light on DotA 6.75 release as it's status was unknown due to combined development of Dota 2. A lot of people are willing to see not just new content but balancing as well and hoping for the map to come out soon...
Final Update (30th September, 2012):
IceFrog releases the DotA 6.75 map with 2 new heroes and an item. Almost every hero is reworked.
New Update (19th September, 2012):
A curious fan commented on IceFrog's profile asking about the release date of DotA 6.75 whether it will be released before or after Dota 2 The International 2012 tournament (TI2) which is commencing from August 31st. You can see IceFrog's rare reply mentioning the DotA 6.75 will not be released until September. So, it looks like we'll have to wait another month for it.. Patience is a virtue!