On TS/Dtail, this was the first build I made since the ladder reset. With a guillame's face + cleglaw's set on switch I slaughter bosses without any difficulty (70% CB total), and with 140FRW (trang arm, 40, sanders*, 40,mav belt, 20, BoS lvl 9-11, 40 or so) I can run straight to them, a bit like a sorc with tele (I just die less than all the pathetic 20-40FCR sorcs in the durance...). So yeah, the build works fine and isn't just dead weight, I could solo up until act IV hell - BUT:
1) killing is pathetically slow beyond 3 players in hell, with a couple of exceptions (my assa runs the mausoleum, countess, andy and meph**). In large parties you're reduced to crowd distraction, through CoS and a good summoned tank.
2) You're physical damage is insignificent - mere fallens ones aren't worth the time it takes to kill them. Therefore you might as well be useless against 2 different immunities of enemy, not one (weak PIs can be killed by unleashing on weak nearby nonPIs).
*I carry a pair of crafted myrmidon boots in my inventory for when I actually get there
**my mf is very low so I message a friend with high mf to deal the final blow against act bosses.