That's a pretty cool idea. I don't like the adoration stacks because Draven either reaches a huge power spike and snowballs after wiping out the enemy team at mid-late game or becomes gold-starved and useless. Although the idea needs some tuning and refining, I believe this change will make Draven's gold income rise gradually instead of inflating or deflating if he is on a killing spree or not.
Something that I think might be more fun and challenging to add is that Draven earns more gold the more axes he's juggling at one single time. Like multiplying the gold earned if he catches 2-3 axes at the same time.