Interesting article I found about the initial proposed Deseret National Bank Building (First Security Bank). It was originally planned to be about the same height as the Call Building in San Francisco, with a similar design:
The Call Building was, at the time, 315 feet - or 123 feet taller than the current building. That's about roughly the size of the WTC at City Creek.
Would have dominated the skyline at the time (almost 100 feet taller than the Walker Center, which was the city's tallest back then).
In fact, the design of the current building kinda looks like the Call - just without the dome: