I think what could be the next big thing is an open source operating system for mining which combines energy optimization, overclocking, heat management, financial reporting, management and so on... Combine that with an open source mining firmware and plug and play solutions so that not only the technical savvy people will be able to mine. Or at least in the beginning. Current mining is not as adopted mainly because of the software/hardeware procurement aspect as well as the fact that non-technical people get spooked, thinking mining is too complicated for them.
Education on mining is still too "self-research"-based, even for people who are somewhat tech saavy. That needs to change too.
I see that there's much more information about mining now than in 2015.
Setting up an ASIC is even easier than setting up a smartphone, but mining comes with its own set of challenges:
power consumption of 3 kilowatts or more, requiring separate wires and a power outlet.
The noise emitted by ASICs is a problem.
And the main problem is the cost of electricity. In Europe and the US, electricity prices are high, making mining unprofitable.