All four points are valid criticism of Relay. Point 1 and 2 especially and the verbose structure of connections is why we decided to offer two endpoints to your project on graph.cool - one that supports all the relay conventions and one that feels much nicer to use.

We decided very early on to use Relay for our main frontend (a dashboard similar in complexity to Parse.) It's probably one of the largest open source projects using relay atm, so maybe having a look at that can be helpful https://github.com/graphcool/dashboard

In summary we have found that the benefits Relay offer makes up for the quirks and complexity Relay currently forces you to learn. Hopefully Learn Relay can help more people get up to speed faster.