[Jeb]

The reason the game includes a strategic view is probably the same as why there's no tactical retreat: PBEM. Since, at least with the current AI, it would be really annoying to have your enemies be able to engage you in tactical combat on their turn, the only fair way to play human vs. human is to use strategic combat only. And, if you're doing a sim turns PBEM game, you can't really use the retreat option.

I imagine the other reason for the no retreat feature is to prevent missile ships, which are already very powerful, from being able to use the "zoom in, launch a few missiles, and then retreat" tactic that made them so devastating in MOOII. Superior speed is already enough of a tactical advantage; if you slower foes don't have a chance to trap you in a corner of the tactical map, you can destroy them with impunity. The boundaries of the tactical screen aren't all that realistic, but they're pretty much essential for play balance.