I don't think that's anything fundamentally wrong with any of the PubSub systems in existence at the moment. However most of them seem to have escaped from or are inspired by the kind of messaging you need at banks and other financial type institutions. This is great and many of the design goals are the same but they're designed to be complicated and complete from the get go. And this works for them.
However I want something more like Memcached or Rails or similar - you install it out of the box and it Just Works[tm] and for 80% of people that'll probably suffice modulo some trivial tweaking.
Then there will be another 10-15% of people who can take that base and after some simple to moderate modifications make it do what they want.
There may even be a further 1% who can make it go even further but, at this point, it's diminishing returns and really if things were changed to make things easier for them it would compromise how simple things are for the 80%. And to be frank, the 1% would probably be better off with something designed from the start to do what they want.
Not everyone wants Oracle - some people are just happy with SQLite and MySQL. Hell some people are more than happy with BerkeleyDB.
And that's a good thing.