A re-alignment election doesn't necessarily mean a landslide. The new "bases" of the party may not be apparent until many years later. For example, even though 1984 did shake up the map, the bases of each party and the real battleground states weren't really clear until 2000. Clinton was still doing pretty well in the south. So I don't think we'll know if a re-alignment election is a re-alignment election until quite some time afterwards.
You could also argue that re-alignments are gradual in nature and not generally apparent after one election. Nixon swept the South in 1972, winning every county in a couple of states, but the region mostly flipped back to the Democrats in 1976, but with smaller margins than before.
