Ha. I'm honestly a little bit terrified of trying to clear the level 34 PoE with any combo other than 3 defender Titans. We spent most of our run last night hiding in each other's bubbles lol

I don't have a whole lot of experience with PoE yet, but it sure seems that invisible hunters are extremely useful.

Honestly, I can't think of anything a Warlock will be especially useful for other than self-revive, which is moot if you git gud and don't die!

Aren't invisible hunters most useful for reviving team mates? Otherwise, going invisible just focuses fire on the other two team mates.

No - invisible hunters are extremely useful because they can go disable the mines all by themselves and without any trouble. Being able to easily revive their less-alive teammates is just a bonus ;-)

I see invis and resurrection as two last resorts that work in different situations. If the entire team wipes at once, invis won't save you. If you're spread out and one person goes down, invis certainly will, and with a higher frequency than resurrection will. As a Warlock I play a lot with a Hunter companion. We rarely stand close enough that an explosion or an errant thrall will take us both out in the same moment. Sometimes (especially with the cabal), if my body is being pummeled I have a better chance as a warlock resurrecting and getting out, than my hunter companion has of getting close enough and reviving me before he dies.

It also seems like "git gud and don't die!" isn't a counter. That could be said about any skill or weapon. The difference is that I can make it all the way to the end and say I never used my super, while the rest of you less gud players are popping supers left and right ;-)

Being able to get to the end and brag about not having used your super is not a good thing, in my opinion. Supers should be used as much as possible. Even if you don't "need" the super to kill a bunch of enemies in a hurry - you should do it anyway so you are generating orbs, thereby helping your teammates. Warlocks (whether Voidwalker or Sunsinger) can very easily generate 8-9 orbs, and if they aren't doing that as often as (reasonably) possible, they aren't helping their fireteam as much as they could be.

Edit: I should probably add that I am not claiming to be good at taking my own advice. When I play Sunsinger, I tend to hold on to that super until it is needed, and as a result I usually go an entire activity without popping my super even once - which isn't as fun for me. Lately, [when I am playing on my Warlock] I've been running Voidwalker more, mostly so I don't feel guilty about using/not using my super whenever I feel like it.