Raising the gas cost on storage I/O has issues (negative side-effects). This was discussed a bit in the allcoredevs gitter today.
I’ll paste my comments here for convenience:
Issues with raising the cost of storage, SSTORE especially, were hinted at in https://eips.ethereum.org/EIPS/eip-2035:
The most problematic cases would be with the contracts that assume certain gas costs of SLOAD and SSTORE and hard-code them in their internal gas computations. For others, the cost of interacting with the contract storage will rise and may make some dApps based on such interactions, non-viable. This is a trade off to avoid even bigger adverse effect of the rent proportional to the contract storage size. However, more research is needed to more fully analyse the potentially impacted contracts.
Similar issues were also discussed at the 1.x meetup in January, by Amir Bandeali (https://youtu.be/CnOyVZ3HvK4?t=900). Amir was talking about issues in the context of storage rent / lock-ups, but some similar side effects would also happen from simply raising the cost of SSTORE, if the increase is significant enough.
Another discussion was in this thread: On raising block gas limit (and State Rent)
- We surely do not need to wait for the entire State rent to be rolled out before increasing the block gas limit. Can we just make state expanding operations (SSTORE, CREATE, etc.) more expensive? Then, recommend the block size increase approximately in the same proportions? For example, make state expansion 3 times more expensive, and recommend raising block size limit by 3 times? Yes, but there are issues to overcome.