In a word? Mundra lag, the more variety of ninjitsu are used the greater chances of getting mundra lag and completely botching it, the two safest to use is Huton and Fuma Shuriken, however doton is great for putting out a dot it can be dangerous to use, especially when combined with Kassatsu....which a ninja should be using with Doton whenever possible as it causes each tick to do more damage on the dot, anyway as I said its mostly due to mundra lag, I myself haven't jumped into alex yet so I'm not sure how much of an impact it will have but from what Ive seen with other nin in dungeons and primals the lag is real, cept for me as Ive seemed to have lucked out :P