Edited 9/29/2015. I added a brief rundown on my build with my reasons for picks.

Plus, I much prefer Shrink Ray at 13 now. Otherwise my build stands.

I am just an average Jo. Low rank Hero League.

Just read my argument before you poo poo me. Lili is far from "useless" as one teammate said to me.

I just told him, "Then you don't know Lili."

Edited 10/29/2015: The key to this build is your serpent is your main source of heal/sustain and the cups supplement the serpent.

I tried the W build on Lili when I was new to Heroes.

Let us just say it did not go well.

This is not for the Heroes beginner, but for a more seasoned player. What it will do is keep Lili fun to play and let you kick some butt to boot.

This build was over powered due to a bug. The bug is gone, but I argue it is still a valid build.

Most of my argument will center on the Level 4 talent of Mending Serpent. But the Level 7 talent should not be ignored. It was often part of my earlier builds. Edit 10/29/2015: Your serpent is your main source of heal/sustain and the cups supplement that heal.

Lili's Q ability is a smartcast ability. It will target the teammate with the most need in an area.

Sometimes you don't want to target the player with the most need. If you know your heal won't save a lost cause, it would then be a waste. You can position to keep that player out of the area, otherwise you will heal him.

Using Mending Serpent allows you to place a heal on a single player you know will be fighting. The heal comes as the serpent attacks. I particularly like to place my W on a tank in the fray.

That way your Q might be able to focus on others or supplement heals on the tank.

Even without the bug, the heal from the serpent is more than a single Q, saving precious mana for other things.

Anyone who has played Lili knows how much she burns the mana. You can replace the Level 1 talent with Conjurer's Persuit, but I prefer the extended time on the serpent to extend the heals and damage.

(Side note: For less experienced players, Healing Ward on Level 4 is very helpful. The ward is easily destroyed, but if placed carefully you can get a good deal of heals. It only has a 60 second cooldown, so you can use it often. It is also mana efficient even if it gets destroyed).

Due to team comp and other factors, Lili can be asked to solo lane. Building into W makes her less weak. I particularly love taking down Illidan in early game. He thinks I am easy pickings. Little does he know.

This also can make you a more active participant in team fights and siege damage. Healing the team is important, but boring. It is nice to provide damage as well. You can spam your Q and kick some booty this way.

This clip shows it in action. Many thanks to MonikerDYT (DYTgames on Twitch) for cutting and supplying the clip. He is a mentor and a friend.
Play Video

The level 16 talent of Serpent Sidekick doubles the above damage, heal, and mana benefits.

Aiding an ally benefits you. What is not to love?

Addendum 9/29/2015: Kung Fu Hustle at 20 lets you pass out the serpents like candy! Great for the core.

Level one: Timele*** Creature: More heals and damage please.

Level four: Mending Serpent: This is the crux of the build. Provides massive, targeted, sustained heal. Even with bug removed, heals much more total than a single Q. Mana efficient. Can provide sustain for tank/melee assassin in fray.

Level seven: Lightening Serpent: Can opt for other talents if needed (ie Good Stuff or Shake it Off). But the damage is nice.

Level ten. Cups yeah!

Level thirteen: I like Hindering Winds, but since writing this use Shrink Ray instead.

Level sixteen: Serpent Sidekick: Double the fun.

Level twenty: Kung Fu Hustle. Serpents for everybody! Okay, maybe not everybody but most of the team.

I went back to Lili after a long stretch of playing other supports. I developed an appreciation of more targeted heals provided by Malfurion and Uther. I wanted a fresh take on this character instead of a more Q centered build I would normally play.

The W build keeps Lili fresh and fun to play. It is well worth a look or, as in my case, a second look.