1. Good thread....
2. For me, the answer is clear: Phogoth in the Summoning Pits strike in Destiny 1
3. Why? It's very simple, in Sept. 2014, when D1 came out, I got by Devil's Lair with not too many deaths, but facing off with Phogoth was way different.
It was a Friday night, after work, around 1am and I was linked up with two other guys, we lost. Linked up with another 2. Lost. repeat. lost. repeat. lost.
I think I finally beat him around 3am. That was a huge sigh of relief. So, to each their own.