There should be more technologies which do not give a wonder, improvement, or unit.
These techs should give social support such as +5% Happiness, +1 happy person,
+20% increase in crop yield, +20% increase in trade, etc.
Adding depth to an important "missing" factor from the original(s)... i agree with you.
Expanding the technologies variety to a point where, not only we have control over much of what's being developped, but also >how< we reach specific paths into some domains.
In fact, true strategy instead of "pacing the steps" through discoveries.
Excellent suggestion.