it is surely good to see someone who is putting some effort into his project and not just copy pasting a script and wanting profit.
i hope you become successful.
But I'm interested to know: Is developing a BTC gambling websites considered to be profitable?
not on its own. people who are using bitcoin have proven to be interested in gambling but they won't go for any game. they usually stick to certain types of games. mostly dice and some of them sports bet.
Can I expect people to pay attention to a new game?
if a new game is interesting they may. but it is a risky move in my opinion to go into uncharted waters.
Is the market maybe already saturated?
it is competitive but it is not full. there is still a lot of room for new casinos to come and be successful. you need a good plan, lots of promotions and advertisement which are all going to cost and then after some time reach profitability.
in my experience, as i said, people don't usually go for newer games that are too complicated and they don't know how to play them. that is one of the reasons why there are a lot of dice sites. because people will always play dice.