RoA is one of the most cost efficient items in the game when it is fully stacked. The item has 121% gold efficiency out of the gate, and 170% gold efficiency when fully stacked. Those calculations don't even factor in the passive on Valor's Reward.
The loss of sustain at level 18 is more than made up for by the free stats you've acquired over time. I don't think the item needs a large buff. It's a huge stat stick that starts as an efficient purchase, and pays off even more over the next ten minutes. The situational laning sustain is just icing on the cake.
Even if it did need a buff, this one doesn't make a lot of sense to me. RoA is theoretically supposed to be an investment that pays off in the late game. This change would be most impactful right after you finish it, during mid game skirmishes, where a mage suddenly regenerating 20-40 extra health per second could easily be the difference between a win or a loss for her team.
Righteous glory is less cost efficient, but it's a relatively inexpensive item that offers a very powerful active effect. I don't have strong opinions either way on this item, but, again, I don't think giving it a lot in-fight sustain is a good way to buff it even if it needs a buff. The item is bought for its active effect--it doesn't make any sense to throw such a potentially huge (and snowbally) amount of mid-game sustain onto it.
