As subject goes, is Bitcoin the maximum version?
Is it still possible to develop it?
You may want to spend a little more time reading about Bitcoin. It's still in active development, and will continue to be for the foreseeable future. There are still a few glaring issues that are yet to be addressed.
Can we still expect better coin than Bitcoin?
Of course. The possibility will always be there, it's the probability that is in question.
Although many people uses bitcoin, it still need a huge development for the users to lessen their problem using it. Its price is very volatile in the market and we can't do something about it because of the way it is being manipulated. There's always a possibility that day by day, bitcoin will improve and makes better services to users as its price becomes high again. You need to read more about bitcoin so that you're updated on what's going on with it.