The biggest need is for a low-energy stabilization method.
One development that may make a huge difference for CEBs is enzyme stabilization.
Products such as Permazyme 11X, EcoBric and others may make possible the low-energy manufacture of bricks and blocks that have weather resistance approaching concrete.
The enzyme products are nontoxic and relatively low cost. $40-$60 worth of Permazyme is supposed to stabilize enough earth for a large house. 1 gallon of Permazyme costs $120 and stabilizes 150 cu yds. 1-2 liters will stabilize a house.
I have been unable to find any builders using these products for CEB (though EcoBric is aimed at that market) but there seems to be considerable experience stabilizing roads.
The original patents seem to have expired, so it may be possible to come up with an open-source recipe for the enzyme. It may not be an enzyme at all. The first product of this type came about when a vintner notice the the waste from wine-making hardened the soil where it was dumped.
Comments at Dirt floor may be relevant