I've worked out what I really think about trends like Mobile First, and have made sense of the way I have been working for years. Read up on my user centric approach to finding the right design, and the right channel, input, and interface, for your product.
In summary, design a target IA to guide all interactive and interface designs, and follow design processes to tell you what channels, inputs and outputs you need to design for. Don't assume web, mobile app, or anything else. Desing for every screen, context, channel, etc.
I am not just pushing for more links to my blog; it's just a long explanation so didn't seem it would all fit here. Anyway, do tell me what you think. I am very comfortable with it, but like the pragmatic parts of the design philosophy, want it to work for everyone. I'll evolve it with useful feedback.