Agave is mostly fructose.
So, superficially it has less impact on blood glucose than ordinary sugar.
However, the way the body deals with fructose is an additional burden on the liver to process.
Fructose has been shown to increase the risk of developing a fatty liver.
Since a fatty liver is one of the main reasons why people develop T2, I would suggest that fructose (agave, most fruits and anything made with high fructose corn syrup) is a REALLY BAD IDEA.