Hi,
As a fellow Ninja, I can tell on first glace that Raiton is way stronger than Shuriken.
Actually a normal Raiton is as strong as a critical hit Shuriken.

However, given the lag sensitive system the Mudras are, is always better to throw a Raiton instead of a Shuriken?

There are situations in which I will not discuss when a Ninjutsu has undisputable priority over the other, for example:

A) A target is 16~25y away? > Shuriken
B) A target is 4~15y away? > Raiton
C) You just used Kassatsu for the sake of attacking one target with a certain critical hit? > Raiton

Nonetheless, the question here is, what if your target is within 3y, Aka the melee range?

As we all know, using the Mudras means a complete halt of your GCD/oGCD rotation, and unlike Katon, Doton, Huton, Suiton and Hyuton (lol what?), Raiton and Shuriken have the same purpose of attacking a single target, one for more than the other... but Raiton is by far MUCH slower than Shuriken, and this becomes even more aparent the higher Skill Speed the Ninja possess, hence Raiton easily slows down the GCD/oGCD rotation while Shuriken still barely feels like a oGCD and barely gets in the way of the weaponskills on the melee range.

I have no way to know which one is better and am curious on it for the sake of optimizing my own DPS as well as the other Ninjas out there.

Is there someone who can try out their DPS on a dummy at least using the rotation Huton > Suiton > Shuriken at 3y from target instead of Huton > Suiton > Raiton?

Thanks in advance