Heavenly Chips are great. But when you start getting to the point when you need over 1000 to get the cheapest upgrade, let's be honest, another single prestige level doesn't really make that much difference.
I think each particular heavenly chip should be worth more. If upgrades are cheaper, then each chip you get is more important.
I think it should be harder to get heavenly chips but each one is more useful once you get it. Maybe the most expensive upgrade is 100 heavenly chips.
1) It ruins ironic numbers, such as 777 for angelic upgrades.
2) I'm not sure how it would transition current players into this new one. I suppose they could divide their current heavenly chips by a number? For instance, you have 10,000 heavenly chips. 10,000/1000 = 10 heavenly chips. This isn't a perfect system, but they should get exponentially harder to get. The first heavenly chip is in the right spot.
3) The Prestige system gets a large nerf.
However, this could be rectified by certain heavenly upgrades that cost 1 chip and are unlocked once your prestige level reaches a specific #. These upgrades would say: Each prestige point earns you +5% CpS, +10% CpS, etc. So basically, 1 prestige level at 1% CpS is +1%CpS, 20 prestige levels at 2% would be 40%, 50 levels at 5% would be 250%, 200 levels at 10% would be 2000% CpS.
That being said, 200 levels is a LOT harder to get to than it was previously. These comparisons were made up of the top of my head and definitely need to be balanced.
These achievements could be called"Because Math", "Differential Equations", and "Theory of Correctness" , or something math/numbers related, and framed so that you are manipulating math to give you more cookies.
Sugar Lumps need their own heavenly upgrade to be unlocked.
Could be named "Sugar Bush".
Upgrades branching off of this could be "Sugar Tree", "Cane Fertilizer", etc. Could add the option of growing multiple sugar lumps at once. Harvesting them could be skill based? This could be a farm minigame, although Orteil already said he was working on those.
Some building minigames should also be unlocked via heavenly upgrades.