Although repricing opcodes can always break contracts, the EVM should be able to evolve too. Clearly, a decent number of contracts will be broken due to EIP-1884, so care must be taken to lessen the impact on the overall ecosystem.
Attack vectors (and their combinations) over xSushi-like staking, ERC777 tokens
Issuing warnings to 100 vulnerable accounts via Etherscan chat
Multi-hundred million attack prevented