Please someone at GGG, PLEASE Play Blood Mage through Campaign

The whole design feels like it’s meant only for twinking a BM or saving your ascendancy until you have all 6–8 skill points, because otherwise you’re just tanking self-inflicted death. In Act 5 boss fights I’m completely drained of both health and mana flasks every time. I was running an Essence Drain/Contagion setup, but leech is hit-based and doesn’t work on DOTs or bleed, so I ended up having to respec. I got into BM for the blood-for-power theme, but right now it just feels like I’m fighting myself to survive. I’m unspec-ing the ascendancy for now, but there needs to be better balance to prevent this.

Bloodmage really is not made for the damage over time package.
You are right that you should wait for 4 levels until you skill into the ascendancy at all and then the big synergy is a crit build.

Last patch I played hexblast crit with it which worked very well for t15 and pinnacle but hexblast got changed.

I think the biggest synergy is going for the physical(bone) spells but something else that works well with crit will be fine too.

As soon as you have the spell leech you do not kill yourself on bosses and as soon as you have crit you will spawn an immense amount of healing orbs.

Another thing you can look into is buffing the remnants with sup gems.
There is a new one that increases the remnants healing but makes them dissapear faster.

I was leveling blood mage hoping for using either detonation or bone magic.. End up only the essence drain is working.
And about the spell leech, it is not good enough. It only makes you survive a bit longer, but will end up using all the potions.
Now I'm thinking of completely respect out of magic build and turn into physical ones. At least physical skills dont require that much health to use.

GGG made Blood Mage so dead that it seems that people aren't really interested in it. I'm completely with you regarding the matter, I started my Witch with Blood Mage in mind only to find out in a2, that phys spells are TICKLING enemies while requiring channeling for freaking 2-3 seconds.. I had a lot of inc spell damage on my talent tree and I got +1 phys wand with a bit of spell damage on it aswell. So I had decent gear to say the least, yet the gameplay was SO BAD, that I swapped to chaos DOTs and never looked back.
GGG, please, give us Exsanguinate and Reap back. These bone spells are utter trash, they are not fun to use, especially after you seemingly nerfed them for some weird reason. I played phys BM before and I got 0 struggles, it was kinda okay through the campaign. The experience which I got day 1 after the nerfs was not just bad, it was straight up impossible.
You have to rework the class. We told you that Sanguimancy is bad even before the release, and more than 4 months are gone and this is still unchanged for some reason.
I beg you GGG, make Blood Mage great. The core concept is so fucking cool...

You just didn't build your blood mage right.
I use Lightning skill to trigger critical. I can be only use one button to apply all my dmg to monster. doing well on all kinds of maps.

How did you guys managed to level from 70 to 80? I tried, lighting, I tried cast on freeze comet, I tried fire and chaos. None helped...I'm blocked