Bittrex I hear has partnered up with a bank and now offers USD trading pairs. This is huge news for the altcoin space for sure. It's going to be interesting to see how/if this will affect Bitcoin in the future.
Fiat trading involves pretty firm regulations, which means that it is very likely that Bittrex will up their verification standards to match their progress. On the more positive side, having a popular crypto exchange make it possible to enter the market directly with fiat, will hopefully decrease Tether's dominance in this market. Nearly all the top exchanges are Tether exchanges, which is pretty worrying. Of course, there is no proof that they are gaming the system, but them refusing to have whatever entity audit their reserves is pretty alarming. If you don't have anything to hide as completely legal business, then what's the point of avoiding an audit the entire crypto market is waiting for....