Fable III: Is it possible to balance the real estate system to maximize rent and keep morality neutral?

I'll do you one better.

Rent levels do not effect your morality over time.

Instead you get dinged initially (when you set it), but when you change it back you can get that morality back. When I tested it, I initially set my properties to high (as I needed money at the beginning) but once I owned all of Albion I pushed it back to low; and my morality came back.

Now I can't be sure it was in equal amounts but it was more than enough to get me over 100% long before the end.

Best bet is to uniformly highball or lowball rent globally.

The game remembers very sharply if you discriminated against the Millfields gentry just one rent cycle just because they were rich - this is related to "Primality".

A chaotic mix of lowballing and highballing is possible, but only creates dissonance in your character's "metamorphosis."

The salvific Kingdom Treasury ledger allows for next to everything to be "morally recalibrated" in the latter portion of the game, in any case... Multiple serial murder - nah, nothing... A few million dollars or gold supposedly cleans one's soul...