I just got this idea about how to use techs for a tactical scen or for one without much technological development (like a Fall of Roman Empire scen). Instead of research, you have military pay, and instead of techs you have differnet units. (Like different legions in the Rome example.) When you acquire one of these techs, events give you the corresponding unit(s). In the Rome example, you ight only be able to build garrisons and auiliaries, and legions are techs.
This makes good military units more valuable and it also means that you get a variety of units - the event-produced ones and the ordinary ones.
Sorry if this has been done already.