I left the game around the time of Heavensward launch, having lost steam somewhere in the post-ARR slog. I got lured back properly after Shadowbringers had been out for several months. One of my favorite early-game experiences was as I was leveling through Heavensward en route to catch up to friends at endgame, when I queued into the Vault for the first time.
I (as healer) go "First time, btw."
Tank goes, "Me too, actually."
One DPS goes, "Three."
I go "Wow, three first-timers! What are the odds?"
Other DPS goes, "...four."
We realized that absolutely none of us knew the dungeon (and all of us were in in gear that was at-best on-level for it, so it wasn't like we were going to steamroller things), and went "Should we go look up a guide?" and decided that nope, we were going to go in blind and figure it out. And it was a blast. Sure, the run took at least 2x longer than it would've with someone experienced pulling us through full-tilt, and we wiped I think twice due to unexpected boss mechanics, but we were really enjoying ourselves doing so. At the end, everyone sort of went "That was the most fun I've had in a dungeon in a while, maybe ever!"
It was that experience that made me so eager to do things like run the Puppets' Bunker alliance raid early on day one, when absolutely no one would know mechanics.
So I totally understand what you mean about doing things blind adding some challenge... and also making them a lot more fun. So I try to remember that when I'm just doing a roulette and end up in some dungeon I've run fifty times and just want to get through it; if someone's there for the first time, I'll try to get everyone to slow down a bit and let the first-timer enjoy the experience. It won't be quite the same thing, since many of us will still vastly outgear the content, but at least it won't be a total zerg rush steamrollering everything.
...I now really want to start a version of this Discord for my data center. A group from my FC (including me) has been doing that with Coils, since people wanted to see the challenge it originally posed (or at least something like it). We finally got through Nael in T9 a couple of weekends ago, and man that felt like more of an achievement than doing anything in current savage in some ways. (Admittedly, this is in large part because I had so many fewer tools to heal with, and basically none of them were oGCD.)