Well, to the stated topic - we need better handling of individual extractions / disconnects. I think DE's working on it.
A few disjointed thoughts...
I don't have major gripes with these Nightwave challenges, and I don't plan to complete them all... I didn't do last weeks Sortie with friends... I could ask someone in the clan, but I usually do sorties when most of the members are offline, and, well, so far I've been perfectly fine with public matchmaking. I didn't do the Hydrolyst, because I just fought my first Teralyst last week. It's out of my league yet, and that's fair.
I don't plan on doing this week's Survivals... maybe I would, if I ever did Kuva survival before, but I haven't completed a single node of Kuva Fortress yet. So... whatever. I find 60 minutes to be too much. The Anniversary 30-min survivals were kinda fun, but as a one-off thing, and that's as long as I'm willing to go. Having this challenge as a reward for dedicated players? Maybe, why not. But I don't care to do it. I'd prefer challenges that can be done in several runs instead.
The Orb Vallis conservation challenge? I might try it. I haven't done conservation before. Just like I didn't do Sanctuary Onslaught before the first week of Nightwave. I like that it encourages me to do new things. I don't play much, and was too hooked up on Sorties before Nightwave launched. And before Sorties, I was hooked up on Alerts (for hoarding credits mostly), which I didn't really like, because it blocked map progression, quests and normal mission rewards.