SLC is not my home airport, but I have flown through several times in the last few years.

The design was / is pretty good. I love having the rental car more or less in the airport.

The Issue, as I saw it, was the "intermediate" status. The one tunnel was clearly NOT designed to handle all the traffic. But they opened ANYWAY, even with a clearly insufficient tunnel.

YEAH, with the main tunnel now open, it's a nice airport.

My analogy....
Imagine we DID rebuild Lavell Edwards Stadium. But decided to play a whole season or two with just NOTHING for the East Stands. You just tell everyone who has had season tickets for years on the east Stands.. "It's ok, when we are done it will be nice. Quit complaining that that the stadium is too small, and not enough seats, and no place for the TV crews to put their cameras. It will be great!"

Somehow, they NEEDED to have a more complete "intermediate" status. The Main Tunnel should have been part of phase 1 somehow. Or you needed TWO intermediate tunnels. or something.