There are many missing features in Google Instant. The classic interface suggested searches from the Web History, so you could select previously typed queries.
It seems that this feature will be available again. Google tests a version of Google Instant with Web History suggestions. For some queries, 3 of the 4 suggestions are from the Web History and there’s only one general suggestion.
Maybe it would be a better idea to only show one or two personalized suggestions, since they aren’t always useful.