There's a serious glut of dice sites out there, and I can't see why anyone would need a new one without some serious twist to it.  There's also just a limited number of BTC gamblers out there, as even a very popular game like poker currently only sustains one site, SwC.  Of course, there's also the fact that most of those other sites were run by hit and run scammers and/or had atrociously shitty software.

But it's not only a tough market to break into right now, but if you do get anything more than marginal success, you will immediately be targeted with a tsunami of bullshit in the form of DDoS, hacking and general cheating and scamming.