So rather than hand crafted quests where there are individual motivations for conflicting goals, the quests should be simplified to the point they are generically interchangeable between almost every character, with no differences at all based on the actual origin?
Doesn't that kind of defeat the purpose of having origins?

Everyone having a wine related quest doesn't solve the problem of someone that has played the game before knowing when a conflicting quest will come up. They wouldn't know which conflicting quest, but they would certainly know when they needed an excuse to separate and get a head start.