WowAce

There are a lot of times in WoW where a quest is given to help guide you to the next questing area (a breadcrumb). However, these quests are not required in order to complete the follow-up quests. To keep quest continuity intact, these breadcrumb quests are no longer available after completing their follow-up's. This causes a problem (more of an annoyance, really) for QuestHubber since it continues to display them even after it is no longer possible for your character to complete them.

What I am proposing be done about this is to filter them out if your character can no longer complete them. I don't know if this information is easily data-mined from Wowhead or not. If it isn't, you could setup your own list of conditional filtering of quest pins. I can give you numerous examples and their QuestID's if you wish. This is just an idea I thought I should throw out.

I actually already have support for this, but it is populated with only 2 breadcrumb quests. This is definitely something that would be nice to do, but it would rely 100% on Wowhead. I haven't looked into it much yet, but it's certainly possible.