As the title say I suggest giving character slots instead of a unique toon.
I often reroll toons after I realize this or that race (or gender) wasn´t right. Currently not much room for mistakes.

It does give two slots.

I´m not sure I understand.
The problem arises for the paying customer not the free player. Or are you saying I can delete any char and get a free char create

When you buy a character slot that increases the maximum number of characters you can have at once. You can delete and create a million characters as long as you don't exceed the maximum.

While I've discovered this through trial and error, it's not intuitive with the current design.