Honestly, if an encounter requires : "all 8 members of a full party to play well and avoid dying" -- I'd say it is well tuned. People are still selling carries so the encounter can definitely be completed by 7 members playing to their fullest ability. If a fight is tuned in such a way that people can make mistakes and it is still clearable, then it's either undertuned or intended to be completed by more players.

If you're getting frustrated by random players in duty finder making mistakes and causing wipes, then there's nothing to be done. You have no investment in these people, no desire to help them, no desire to teach them, and no desire to help them improve. You're just going to wipe until you get frustrated, leave, and get new random duty finder people.

Part of the joy of learning encounters like this is learning them as a group. I down T5 on two characters every week in two static groups, and even though I had killed Twintania before either of my static groups did, it still felt so much better to finally do it as a group. We spent hours learning together, and although people learn at different rates, and sometimes we got frustrated over this or that -it paid off, and we finally did it.

EDIT: this is specifically regarding "8 people have to not make mistakes for 10 minutes"

as for Titan itself, without lag I think there is no issue at all with the encounter. It is no doubt exceptionally frustrating for people with high pings though.