Since upright-facing warp pipes underwater can push players/entities upwards (similar to Soul Sand), I think it could be cool if downward-facing warp pipes could push players/entities downwards (Similar to the Magma Block), and sideways warp pipes could push players/entities in their respective direction.

Here's a screenshot demonstrating the idea using a Magma Block and an Encased Fan from Create:

Simple/Minor Idea, but I think it could allow for more unique ways of utilizing warp pipes for underwater builds.