Shadow Lightning tendrils Crit build criticism

Good Day

Ive been playing a Crit Shadow Lightning Tendrils since the start of the leauge and i find it realy fun, clear speed is nice but i feel i lack in boss killing ability, The Plaza boss raped me hard and i have big issues with some of the red map bosses.

So i was mostly wondering if anyone has any tips on changes or ideas or things ive missed or been retarded about.

Im using the weapon as a 6L as with empower and a lvl 21 lightning tendrils gem i reach extra AOE but if i get my hands on a 6L chest i might switch around abit.

One problem i face is that when i do single target dmg for some time my mana deplets so i would like some tips on more mana regen.

Gear:


Tree:


Im bored at work atm thats why im not doing a poe builder link.