I'm not naming names here, but there is something I've consistently noticed among many blockchain-based applications. The idea is often great and technically sound, but the UI is terrible.
And this isn't something I've noticed specifically in blockchain apps; it's also a problem in open source. You can tell when a developer has had to put on multiple hats (developer and designer). More often than not, brilliant developers cannot design to save their lives. I say this as a developer myself, most developers who attempt design fail.
Call me shallow, but I believe blockchain has failed to achieve mass adoption despite every year the promise of it materialising is mentioned because the design of many dApps is not only terrible, they're UI's that assume the end-user is familiar with blockchain concepts. Everything is so much more difficult than traditional web 2 user interfaces are.
And a good UI is more than a pretty design, it's also about the user experience (known as UX). There's how it looks and then there is how it works and feels. Apple mastered this under Steve Jobs. Phones had terrible UI's until the iPhone was released.
So, what's the solution?
Better UI's, of course. Not only is the look important, but also the feel and usability. Developers should lead the work on their apps but also consider paying or partnering with a designer to give their applications much-needed polish.
It's easy for a developer to get caught up in the idea of something, to finish and launch it with the promise of making it nicer later on. Design isn't on the minds of developers (well, most, not all). And I can attest to this because I am a developer too.
I love nice-looking things like the next person, but my design skills don't extend far beyond CSS frameworks.