So thinking about the server lag issue with NIN, and one thing came ot mind that would really help it is a mudra builder UI that shows you where you are in the current mudra going by what the sever thinks you're mudra is. We'd see the ninjutsu skill in the top part of this UI element with the current ninjutsu, and the mudra used to make it below (for example, I'd see Houton as the ninjutsu with Jin Chi and Ten below in that order). This would work by putting a grey box with a question mark in the builder, and leaving the Ninjutsu as the default icon. Once the server confirms that you have used a mudra, the box would change to what the server thinks was used, and the ninjutsu would change according to what's being built.

This would be a useful UI for the less experienced because it's showing you what you're building as you're are building it. For the vets, it would let you know what mudra the server thinks you're building, and essentially give the vets an easy way to slow down and work around the lag issue, as you're going to want to wait to put in the next mudra once server confirms your last mudra (that is, the grey question mark becomes the last mudra used).

All in all, NIN has been a lot of fun, but the randomness introduced by the lag has not been - and hopefully this idea helps minimize that RNG.