Bitcoin already has a sigops per block limit to mitigate the risk of this attack (despite the FUD that introducing such a limit is all that's needed to solve the problem, which is pretty dumb considering that's already what happens

)
cores limit is not low enough
MAX_BLOCK_SIGOPS_COST = 80000;
MAX_STANDARD_TX_SIGOPS_COST = MAX_BLOCK_SIGOPS_COST/5;
who the damned F*ck should be allowed to build a single tx that uses 20% of a block!!
who the damned F*ck should be allowed to build a single tx has 16,000 sigops!!
lower the TX sigop limit to something rational and you wont have the worry of delays due to sigop validation
also. one thing CB is missing out on
Core would not because they're all convinced we must have segwit before increasing the block size to prevent a quadratic scaling sigop DDoS happening... though segwit doesn't change the sigops included in regular transactions, it only makes segwit transactions scale linearly
meaning native transaction users can still sigop SPAM.
segwit has nothing to do with disarming the whole block.. just segwit transaction users
again because carlton is not quite grasping it
though segwit doesn't change the sigops included in regular transactions,