Make all Tor nodes obfs3 by default
As we all know "Brazilian TV news show Fantastico showed screenshots of an NSA tool that had the ability to identify Tor users by monitoring Internet traffic." as part of the FoxAcid program https://www.schneier.com/blog/archives/2013/10/how_the_nsa_att.html
Since obfs3 will make it much more harder for ISPs and other surveilling entities to detect Tor traffic and hence identify Tor users and operators, all tor nodes should communicate with each others via obfs3.
This implementation is very easy, does't require special hard work, will make Tor users/operators safer and more secure, harder to identify, will make Tor traffic harder to decipher, and above all there is no downsides for it especially in terms of resources and power consumption.