Give all the jungle items a unique "sated form" and use "conservation charges" for getting sated.
So once you complete your jungle item, every 40 seconds it gains a conservation charge. It can store a maximum of 3 charges. Kills/assists on large/epic monsters and champions expend 1 of these charges if available. Expending 1 charge grants you 1 stack toward getting sated as well as say 50 bonus gold, regardless of what you took down. You need 20 stacks for your jungle item to get sated. So it will take you a minimum of 800 seconds to get sated, regardless of whether you spam ganks or just afk farm. Once you are sated you still passively gain up to 3 conservation charges but expending the charges only grants the bonus gold. The bonus gold can be adjusted if it seems OP compared to the old spirit stone items but keep in mind the jungle camps spawn much less often this season.
Devourer: Same as it is now but grants one on hit magic damage on-hit per stack instead of the awkward 0.666... as you can only get 20 stacks now so it will still top out at the current 50. Sated: Same passive as now.
Cinderhulk: Same as it is now but also give it the unique tenacity stat that mercs and zephyr have, so that jungle tanks can build ninja tabi like they want to. The cinder passive now does 10+1 per stack magic damage per tic instead of scaling with level. Sated: The cinder field upgrades to do an additional 1% of nearby enemies maximum health per tic as magic damage.
Runeglaive: Same as now but each stack grants it an additional 1 AP, passive the same too. Sated: Reverts the nerf to the original runeglaive passive, except maybe the bug where it was applying spell effects.
Warrior: Same but each grants an additional 1 AD. Sated: NO CLUE. ANY IDEAS? It should definitely be something that makes the item slot efficient late game so you don't feel the need to sell it.