Played it a bit farther up to lvl 90 timelines and tested how it feels vs Echo Endbosses / T2 Dungeon and various versions + levels of Orobyss. I included all fights where my Spriggan died as well to show the difference in boss damage without it.
I have to emphasize (like in the OP) that the Spriggan is actually very important in boss fights and contributes like 50% of overall damage (including its buffs). So in my case i have to get at least 100% inc minion life on top what i have now so it’s more sturdy and more leech as well.
Here are new video logs in early / mid monoliths in the level brackets: 69-73 & 75-81
Current spec + items: