I think there is no need to modify the Hive at the blockchain level as there is
max_accepted_payout. This parameter can be set between 0 and 1000000 HBD.
For short-form content, this parameter could be set to 1-5 HBD and the post payout will not exceed this. Everything above this threshold will be returned to the reward pool.
You can see here how it looks when the parameter set to 1 HBD:
When auto voters are checking this parameter, it can be used to mark a post as short-form content.