I thought I would contribute a little. I play only hardcore so not dying is essential to me.
So far i've tried these builds:
Pathfinder BladeVortex, peaked out at around T5-T6 maps, then died to oneshot.
EQ Slayer, was really good and easy to level with as long as you had twink gear, peaked out at around T3 maps but did them very fast and extremely safe.
SRS, Zombie, Spectres Necro, it's what i'm doing right now and it's pretty clunky and slow, spectres has to be manually summoned.
King/queen of the forest, barrage single target and lightning arrow as aoe, created my own CR for this one, was absolutely amazing, decent clearspeed and cleared up to T12 without dying. Much thanks to the custom CR tho.
Do you guys have any experience about hardcore?