In the last days I did a lot of Slaughter Shaft M3 sessions and here are my personal conclusions:
I find Eager to Impress redundant. The majority of my cooldown is always burned with Head Count and the cooldown guardian perk. I prefer Self-Repairing System for +30 % health and 1.5 % health regeneration.
The Re-Router is a nice shield, but for M3 Slaughter Shaft I need some serious defences. The Re-Router is depleted or half full in most cases and so it will not trigger the cooldown guardian perk. I prefer the Transformer, Stop-Gap or the Ward. The last one offers +25 % gun damage and 4 % health regeneration when depleted. Together with the spiderant and Self-Repairing System I have 6.5 % health regeneration (7.4 while moving) outside of Fade Away. The Brawler Ward also offers +300 % melee damage when depleted, which brings us to the next point.
A Knife Drain artifact is a huge bonus to survivability. With 75 % melee life leach and the Brawler Ward you are almost invincible! Just keep slashing in critical situations and every hit will heal you from almost zero to full.
And to make it better: The Face-Puncher shotgun counts as melee damage and will heal you with 75 % life leech! Better than Salvador in BL2.
Lucians Call is still great. But if there are only a few enemies (so the ricochets won’t hit anything) or they are far away I prefer the Night Hawkin to burn the cooldown. After the nerf the effective range of Lucians Call is significantly reduced.
Thank you very much for writing this guide. In these days everybody creates YouTube videos and well written guides are becoming a rarity.