Think Heinz Lofts (condos, not ketchup); the Freight House Shops at Station Square (retail and restaurants, not rail cars); the History Center (cool exhibits, but no longer any ice). You get the picture. Preservation allows for considerable modification and changes in use.
As an arena, I might concede that the Igloo is "outmoded." However, as a repurposed civic center, it is far from "finished" — unless the Post-Gazette's apparent standard of "no developer has stepped forward" is given any merit. But by that argument, the Penguins' plan is equal fantasy.
Lastly, can this paper please help to once-and-for-all stop the disingenuous assertion that the Pens' development plan "restores the street grid of the lower Hill District"? You are repeating specious claims, which had they been investigated, would show that the street grid within the 28 acres of the Lower Hill contained approximately 11,340 linear feet of named thoroughfares containing buildings with street addresses. The UDA plan proposes approximately 4,810 linear feet of streets, or roughly 42 percent. Few of these would be located where original streets were located because of the large, nontraditional block sizes being proposed — far from "restoring the grid."