So today if you make a new character he’s as you are used to, a fresh character with no reps or resources of his own. You can continue on with that character as he is if you so please or you can jump him into have him join your “Character Alliance” and he would have access to “things” 
What things? 
Whatever Blizz decides but an example could be the renown the farthest progressed character (covenant wise) in the Alliance has achieved.
This would prevent the thing I mentioned earlier from being a problem
If you don’t choose to join your character alliance then new characters are as they currently are but if you do join then you get the Alliance perks