But I'm interested to know: Is developing a BTC gambling websites considered to be profitable?
For me ,it depends knowing that BTC gambling and altcoin accepting is good .It will be profitable if your Gambling site have many players.
Can I expect people to pay attention to a new game?
Yes, especially if it is interesting gambling make sure to provide a tutorial and some videos how does game works before they play .In that move you will know how they will feedback and be excited or not in your new gambling game.
Is the market maybe already saturated?
Not already , Just believe and do what you think would be great and unique for your gambling site to be competitive than others .If your gambling site is catchy and added some unique different taste from gamblers sure it will be worth all your works.