I have homebrewed various additional elemental disciplines for the Way of the Four Elements monk subclass. Although many of those are just adding more spells (erupting earth, tidal wave, etc), and others are just reskins of existing disciplines (such as fist of unbroken air, water whip, etc), one unique discipline that I came up with was this:
Water Jet (11th level required). You can spend 2 ki points as an action to unleash a jet of water in a line that is 30 feet long and 5 feet wide. Each creature in the line must make a Strength saving throw, taking bludgeoning damage equal to your Martial Arts die + your Wisdom modifier on a failed save, or half as much on a successful one. In addition, each target that fails its saving throw is pushed up to 20 feet away from you.
However, I wrote this a while ago, and I can't remember why I decided that it should cost 2 ki (which is typically what the disciplines you have access to at 3rd level cost) but also be given a requirement of 11th level or above.
Intuitively, this feels like it would be fine as-is for a 3rd level Wot4E monk to have. Either that, or if it is to have a level requirement, the ki cost should match that of the other disciplines that have that same requirement (e.g. 4 ki points for an 11th level discipline, not 2 ki points).
Compared with the RAW elemental disciplines from the Player's Handbook, would this discipline be balanced if I removed the level requirement?