Follow up to my discission on this from AllCore Devs #120 (https://github.com/ethereum/pm/blob/master/All%20Core%20Devs%20Meetings/Meeting%20120.md)
I brought this up as the scope of precompiles is growing for L2 and alt-eth chains. In particular all L2 chains have at least one system precompile to initiate exits back to L1.
The proposal was to make this proposal impactful by making the whole range “warm”. Martin pointed out this would re-open the broken metre attack.
After thinking about it for two weeks I think the way forward may be to re-open EIP-1109, which is a PRECOMPILEDCALL opcode, that would fail if it called anything but a precompile, and mix it with EIP-2046, which wanted to reduce precompile costs but not make them zero. The proposed fee would be the same as all other CALL series for warm calls, and any call to a non-precompile (as determined by the chain, so hard forks and other-chain additions like L1 exit precompiles would adjust that set) would fail consuming all gas.
As far as when… the next “open” hard fork. It’s not important enough to drive a hard fork and not essential to the merge.