Some people mention Lightning Network. I looked through it. look at the positive side, LN helps faster transactions and will help Bitcoin price increases. however there is some risk of application LN.
I feel as though the risk doesn't outweigh the reward though. Someone correct me if I'm wrong, but having instant transactions and no fees literally puts bitcoin up with the big hitters like Paypal. With the cryptocurrency aspect behind it too, I don't see why people wouldn't want to start pumping their money into BTC. The lightning network could easily solve the issues that most people have with bitcoin as a currency and influence those who refuse to invest in it. Also, as a correction to what you said, I don't think I'd say that Bitcoin is the most secure because of the high market cap. I don't think market cap really has much to do with volatility; Bitcoin can be super volatile regardless of where it ranks in the market caps.