A B737 Check Airman witnessed several go arounds because of unstabilized approaches on the LAS 1R visual and suggested that LAS TRACON move the visual approach crossing restriction to 170 kts at 7 nm. The B737-700 does not descend well.

Narrative

We were vectored off the SUNST Arrival to an east downwind for (initially) Rwy 1R. ATC changed our runway just prior to our base turn and called out our traffic to follow. The Pilots called the field and traffic in sight. ATC stated we should maintain 170 to a 5 NM final. Being high and with a 3.4 degree glideslope; the Pilots could not get the aircraft slowed down and it resulted in a go-around since we were not stabilized. Good decision by the Captain. I had personally flown the same approach twice the day prior and had to configure very early to be stabilized at 1000 ft. My safety issue is that I believe ATC is forcing us to push the field with the 170 knot/5 NM final. This is especially true considering the fact that Rwy 1L has a 3.4 degree glideslope. It is hard to get the -700 to slow down even when you are on glideslope. If you are high at all; which happens on all the arrivals to Rwy 1L (KEPEC or SUNST); it is very difficult to meet our stabilized approach criteria. I would recommend speaking with LAS Approach and asking them to push the 170 knot/5 NM callout to 170 knot/7 NM final as a minimum. I also say this because I have seen more go-arounds on line checks for arrivals into Rwy 1L/R in LAS than any other runway in the system.