My memories of the Metrodome have a few different phases:
1. As a kid, the place seemed like magic. Baseball games with dad / uncle / occasional school group because the knothole prices were cheap. At that age when major league baseball was special, the Metrodome was special. I even remember watching the Timberwolves play their first NBA games in the Metrodome, though upper deck seating for those games wasn't great. I think Michael Jordan was playing in one of those games, but you couldn't really see anyone's jersey or have any idea who was going in and out on that basketball court way down there....
2. As I got older, so did the Dome. After the '87 and '91 teams when Minnesota baseball went into a decade long slump everything just felt worn out and tired about the experience in the Dome. The lackluster baseball probably had a lot to do with it, and by the time the late 90s rolled around "fun" was in St. Paul; the Dome felt empty and kind of sad in comparison.
3. The Dome also had the memories of trips to see Iowa @ Minnesota football games, when the Dome was a giant roadtrip for Iowa football fans. Of course, said roadtrip also meant the Metrodome became a code word for joking about idiots realizing that you can't take the goalposts out of an indoor stadium, or drunken bathroom trysts. (I've been in those bathrooms - yuck city.)
4. The stadium fights. The Metrodome became a symbol of all the things that didn't work by trying to keep the Vikings happy, the Gophers happy, the Twins happy... and no one was happy.
All in all, I have a certain nostalgia for things that happened there - but I don't really have a nostalgia for the place itself.