Next big thing would be acceptence of Bitcoin and other crypto coins on a real-time basis which is bit difficult due to volatility, developers should focus on how to make cryptos usable like any other online payment method or the purpose it's developed instead of just leaving it as a investment medium because the core objective of crypto coin is to make our lives easier and upgrade ourself with next level of technologies which is need of the hour.
I feel Bitcoin and other altcoins needs to focus on adaptability by having tie up with tech startups and gradually move on to wider range of audiences.
It will be difficult because there will be cables needed like in the Stock Exchanges so the prices are relayed as fast as possible. This will not be just developers in action because infrastructures are involved if we want to achieve a real time basis for ever fluctuating prices of bitcoin. I think that adaptability is already happening with more tech giants integrating blockchain technology on their system like Paypal, it will only be a matter time and all systems requires to be blockchain integrated.