The only part that is messed up to me is what the OP was asking about. Getting a Major Adventure and sending a companion out on it only to find that you will have to complete EIGHTEEN quests before it is finished is kind of stupid. And for what? An average item and 15% XP? Wow...
I guess I won't be sending any companions out on quests if I ever intend to have them back in the party.
It all should have been time based IMO. I guess the taxes could be Quest based but they are so puny it's not like it's something that can be abused to get rich anyway.
It's no big deal really since it's all optional side stuff, but it could've been done a little better.