I just looked it up… Delta is replacing all of their 747's anyway, but they are purchasing roughly 80 new wide body aircraft, thats a lot considering they are only replacing 29 older wide body aircraft (767, and the 747). These wide body orders however, are mostly A330's and A350's (the equivalent of a 767 and a 777 for the uncultured) meaning we could see quite a few large airplanes at the new airport along with current 767's, 787's, 777's, etc.
The plan shows the airport capable of 4 wide body aircraft in phase one, and 8 in the complete 2030+ scenario (with the paralleling island concourse). Perhaps this increase in large aircraft and the capability of such aircraft at SLC, SLC could see an increase in long-distance international flights in the coming years. For comparison Denver is only capable of handling 6 wide body aircraft at a time.
Also if you are thinking "well maybe these larger aircraft are to replace multiple smaller daily flights with one large one" that is most likely not the case, as delta continues to increase smaller flights at hub airports and has ordered roughly 150 smaller aircraft such as the 737 and the A321, and will only be replacing a handful of 757's while doing so. This is just speculation but this could spell the growth of delta airlines, locally and internationally, which has already been seen in the massive growth into the far east. Perhaps SLC will see some of that growth…
Also, I have a relative who used to fly the larger planes for Eastern Airlines, (before all the crazy happened) and he's been following the Seattle delta growth and the expansion at salt lake, and says most likely Seattle is a temporary (10 year) western hub for delta, as it is already crowded and serves most of the same flights within the same distance as SLC, therefore SLC could take over the Asian operations from seattle once the new Airport is complete, it would have better connections, flexibility, reliability, and capability than the currently floundering Seattle.
Good things could be in store for SLC international airport, Just saying...