I think all of the problems you bring up are indeed hard problems, and important ones to work on, but they are also problems that exist already, in the current

I think all of the problems you bring up are indeed hard problems, and important ones to work on, but they are also problems that exist already, in the current ecosystem of open source web apps, and even often in proprietary apps. About the only way you get "cohesion" on the web today is by limiting yourself entirely to services from one company (Apple; Google), and even then it's far from seamless. Yet, somehow we make progress. So our goal is not to solve these problems, but to incrementally improve the state of the world. Clearly, the first thing that needs to happen in order for open source and decentralized web apps to be viable is there has to be a way that common, non-technical users can actually use them. Sandstorm is trying to offer a solution for that, and we think we're pretty close. As much as possible, we actually try to stay out of the question of UI or API standards. IMO that's a problem that can only be solved organically.