I know that with Beta 3, gameplay and balance are starting to become issues for us to explore. But that doesn't mean we aren't also searching for bugs, seeing how various spells work, and taking a look at the endgame. With access to a few cheat codes, us beta testers would be better able to try out extreme scenarios, see how endgame battles work out, and just get a better feel for what kind of powers you units can potentially gain. Here are some basic ideas.
Resource Cheat: Self explanatory, gives a bunch of Gildar, supplies, metal, etc.
Level Cheat: Levels up the selected unit.
Research Cheat: Finishes the current round of research.
Teleport Cheat: Teleports selected unit.
Build Cheat: Finishes all units and buildings a city is constructing.
Spellpoint Cheat: Gives a bunch of spellpoints to the selected unit (or maxes them, if the former is not easily implemented)
Judging by the developer videos, some of these are already implemented, so putting these together shouldn't be that hard. Who else thinks adding cheat codes would be a good use of the devs' time?