Possibly outwith the scope of this mod and worthy of a separate one, but since this deals with liquids it might be a good idea to bring this up anyway.

• Fluids attempting to connect to other diagonally adjacent fluid blocks (MC-70848)
  

• Fluids attempting to connect to other fluidlogged blocks where they cannot (MC-127030)
  

• Water bulging in an arrangement of four stairs (MC-127270)
  

• And maybe make fluid textures scale up depending on what direction they flow in (up to sqrt(2) for diagonally flowing) to soften the horrible grid lines you get especially on lava (MC-129207):
  

probably better to leave these kinds of rendering issues to sodium

Moved to CaffeineMC/sodium#91 since it probably fits better there - feel free to reopen if you think this mod would be better for fixing it though