I don't think susanoo is even the ultimate defence for two reasons;
1. Gaara was able to penetrate it with his sand.
2. Raikage also sent it flying with a blow.
There isn't a single perfect defense against all attacks. there are perfect defenses for specific styles. such as;
for ninjutsu, the perfect defence is the ninjutsu absorption ability provided by the rinnegan.
for taijutsu, u just have to be faster and punch harder than ur opponent
for genjutsu, must be either a junchuriki or have perfect chakra control or better still have a more powerful dojutsu.