1. Volatility of price of bitcoin is there which makes it a prime target for traders. bad news for stores/shops
Very volatile indeed. 
5. Irreversibility of transaction - though I consider it as the least because it is a fault of the user to mis-click and not system. However we are all human and we tend to make mistakes.
That's a feature of a immutable chain, not a disadvantage.6. Some people consider bitcoin = hackers, drugs etc since we all know about ransom-ware, and many people came to know about bitcoin from ransom-ware, Silk route incident etc
This is not a disadvantage of Bitcoin; it's just a misconception.