Are you asking for Energy Drain's graphical effects to be changed to that of Leeches? Or turning Energy Drain into Leeches (ie. Esuna) but with Energy Drain's animation?
Or... Are you suggesting an additional effect for Energy Drain that would function as an esuna if used on a party member?
OR... Are you asking for Leeches to come back?

I'm sorry, but I don't really understand what you mean. Energy Drain and Leeches have nothing in common. o.0