Hello there!
The newly added quests for C/B/A cards after x finished Runs are a really nice addition to make higher Dungeons more rewarding. However one small addition I'd like to suggest.
As you still need quite a few people to clear the Dungeons and time to coordinate Up to 8 people on a regular base is Not that easy, people with several Chars as "flex picks" (Like one Tank, a Support and a mage aoe/dps) get punished in Quest Progression due to swapping characters to fill needed slots.
To counter this at least a bit it would be nice, If said Quests were Account linked, so different Characters on the same Account could still contribute towards the Overall Goal. This way the people that flex pick don't need way longer to finish the quests.
I get that Long Term there won't be a big difference, but this would take away the necessity to finish up to 49 additional Runs If you substitute another role every now and then