Agreed would love something like this or simply make them alot cheaper to awaken, it's annoying having to wait days and days to use a new ninja just because hes too weak when not fully awoken, especially as you get higher, takes alot to full awaken 1 ninja.
And you need to change teams alot, SA, Exams, Survival, Ranked and normal battles, thats alot of ninjas to awaken.
Don't play it anymore but League of Angels 2 had this, recycle old hero's and it returns everything you used on them, money, materials and all, was nice.