The future of bitcoin is very complicated. But it's already starting to transform the financial world dramatically. Everyone knows it's great for the black market for sure. Bitcoin is completely revolutionising remittance market. In china many people who is working in US are sending money back home using bitcoins to save money transfer time and same time they also can save transaction fee about 2 to 3%. The global remittance market is worth about 600 billion each year. So things are looking good for bitcoin. Acceptance will grow as more and more people use it and it will surely will grow in long term.
What I think is future of bitcoin looks pretty bleak. There are some very big scaling issues. The distributed nature is a problem because every bitcoin node needs to know about every transaction that is ever made. Right now the bitcoin network can only handle around 7 transactions per second globally (this is what I know) and its not clear how these limitations could be lifted. Just increasing the transaction limit would lead to a huge blowup in the bandwidth and disk space requirements for maintaining a bitcoin node. This will surely make it very hard for bitcoin to reach grow bigger scale.