GreatEye and spill, please explain why what I proposed will not work for you:
Favor for unlocking builds is account-wide. Merge the favor credits from all characters on your account to obtain total account favor. You retain any gains made by deleted characters. Use one character, or many, to explore all the content. The result is the same as far as build rewards are concerned.
Seems to be the perfect solution for the obsessive reroller. You get to play and reroll as many characters as you want. There is plenty of favor to hit 1750 even if you stop at level 10 each time. Why wouldn't this work?