Assassin/Ninja Chat, is this a good build?

This is a modified version of SugVon's Ultimate Build Guide Weathered - Shadestepper [DMG VARIANT]
I've changed it to more fit my play style of high attack speed, because I loath moving any part of my character at less that light speed. Tell me what you think.
P.S) I had to use a picture since I can't post links yet.

 

The issue is with how mana-steal works. Having anything above a super-slow attack speed for spellsteal builds is a bad idea, as it means that the mana you get per hit is reduced increasingly depending on how many times you can use your melee per three seconds.

To illustrate my point, with around 60/3 mana steal and a super-slow attack speed, you can get ~ 40 mana per hit with a .5 second hit cool down. That's ~ 40 mana almost instantly. However, with a fast attack speed, you need to hit around 10 times to get that same ~ 40 mana, and 10 attacks take much, MUCH longer than one single attack.

That's also just not enough mana to sustain anyway if I'm going to be honest.

 

I see, is there anyway to have high mana sustain without mana-steal while maintaining super fast attack speed as well as high spell/main dmg?

 

You’re never guess what I’m gonna say next, mana regen

 

Thank god you're using Weathered, it alongside Nirvana are the only weapons that make mana-regen shade viable.