Org mode approaches this by making hierarchies and inheritance optional. I personally like both, but I acknowledge (as was mentioned in the tweets) that hierarchies can get to be very convoluted if you don't work to maintain them sensibly.
What I like most about org mode tags is that regular expressions can be subtags (or "members of a group tag" in org mode lingo). So you can specify a hierarchy where the parents have children you don't know in advance.
