IIRC, the ancient A concourse will cease to exist once Terminal 3 becomes operational on June 27th. Also, the even more ancient Terminal 2 is slated for death once Terminal 3 opens.
Terminal 3 is a sweet addition but will only provide 7 domestic gates as it's main purpose was to expand international capacity. United & Hawaiian will operate from D gates but have check-in & baggage @ Terminal 3. Those folks get to take a ride on the brand spankin' new underground tram thing-a-ma-jig connecting Terminal 3 to D concourse.
If you fly Alaska, JetBlue, Sun Country or 2 others I fail to recall at the moment, then Terminal 3 (E gates) will be your new home after June 27 when you fly into/out of LAS
And yes, Terminal 3 has good eats