Gas Abstraction is possible thanks to CREATE2. An update of the mining/validator node (no hard fork required) would be important to enable gas abstraction, so this “meta transactions” can be included directly by miners, which configure ERC20 they accept.
An optional EVM consensus change can be implemented to support “validator functions” in the contracts, which would enable block creators to call a contract without a sender, this special transactions cannot use msg.value or msg.sender and requires gas.price == 0, and only have destination and data, and if fails, then it would cause an invalid block. This transactions would be used to call the gas relay functions, which would use block.coinbase for the meta-transaction ERC20 gas payment.
Is this idea bad? Seems so possible and good to end users.