'The character may trade-in a rarely skill purchased at character generation if he feels it no longer fits the character concept.'

should be:

'The character may trade-in a rarely used skill ...

Also, skills purchased after initial char gen cannot be traded in?

Suggest:

'If a player purchased a skill during character creation but rarely uses it or feels it no longer fits the character, he may trade-in that skill for half the Destiny it would cost to purchase it.'