My suggestion is to increase the time span of guild quests to 2 days. Not only we have more time to do the quests, but also we can see the next quest in waiting list and prepare for it.
One more thing, I learn that if I don't finish my guild quest, I won't get any guild coins, not from my personal quest nor from my guild progression. As I remember, in the old system, all guild members got the guild coins from guild progression. We know that not everyone can finish their guild quest. We were always happy to share with them, that's what the guild is for. If you think it's "unfair" somehow with the new system, just reduce the amount from guild progression, and increase the amount from personal quest. But no matter what, when the guild quest is reset, every guild member should receive the amount from guild progression. We, the level 51+ players, are now stuck with fairytale-adv guild quests. We can't finish our own guild quests, but we still help the lower level members to complete their quests.