The offerings through the mail basically climb the ranks of the Lore Skill which is why garlic wreaths etc start arriving. I like that as it makes for good story telling if your sim is a vampire hunter reading up on vampires and gaining the knowledge necessary to slay cure them.
To be honest, the developers have a hard road trying to cover all 'types' of simmers this time around due to the way in which the content is delivered. It's a very different model than TS3 and the developers are led by the managerial decisions, not the wishes of the gaming community. The key for them is to try and get as much flexibility in each pack as possible. It's easy to point the finger at 'the devs' and I have been guilty of doing that in the past too, as if 'they' aren't individuals going to work each day and doing their best, but some kind of anonymous blob that are guilty of all crimes against gaming!