At the moment, all evars are of two types i.e. string or counters.
However, for several industries - like travel (departure date, check-in date), discount sites (deal expiry date) etc., dates need to be captured. There is no easy way to then filter out date ranges for the evar. (Doing SAINT classification for every date range one might want to select is insane). Similarly, for numeric data like price, quantity, visit number etc. filtering out reports for values in certain range - there is no easy way.
Allowing admin to specify data types and thereby providing compatible ways of filtering out data would be a great help.