
Onto my point: I'm considering adopting a Mass Effect and Star Wars: Knights of the Old Republic approach where the player is locked into a true neutral alignment. Decisions will impact their alignment over the course of their story. A starting alignment provides me a base-line, so I can better direct some of the content.
This alignment restriction also makes sense from my story's perspective. Your character is a young woman who has lived a fairly sheltered life under her father's roof. As she exits her final year of home-schooling, she's uncertain about her future as her father pressures her into joining the Church of Knox. She knows very little about what lies beyond her city's walls. Many of her adventures were spent inside the pages of fictional story novels. Due to her inherently benefiting from her father's wealth and prestige, she lacks a morale compass regarding concepts of money and power. Basically, it's impossible for her to be Lawful Good or Chaotic Evil, because she doesn't know what good or evil really means.
I find the protagonist's lack of understanding interesting from a character-study perspective, as she will be tested by various authoritative figures, most notably her Church's instructor, Malakai Varus, who isn't shy about taking advantage of her. Several more opportunistic characters will await the protagonist. How you confront them will shape the kind of woman she becomes.
Anyways, I'm aware some people hate being forced into a starting alignment, so I'm open to your thoughts. Of course, it's your decisions that will matter the most and not necessarily your alignment. Your alignment will simply be one of the consequences reflected by your decisions.