I want them to be more expensive at compute and block template construction, you have to mine the TX to the specified difficulty. So whoever is constructing a block template has to put that work in before even mining the block itself, It would, in effect, lower the difficulty of the network too, since some hash is diverted to block constructions and would make the incentive to mine the most monetary based tx that have little or no op_return in them over bloated non-monetary txs.