Villager "service" trades buff

"service" trades refer to ones where a player gives an emerald + raw product in exchange for "process" products, EG: 10 gravel + 1 emerald for 10 flint

The service trades that enchant books are powerful, as are the fletcher potion arrow ones (ASSUMING YOU GET A USEFUL EFFECT, NOT NIGHT VISION). Most of the other ones are not powerful enough.

The issue is, if you make the gravel for flint trade 32 gravel + 1 emerald for 1 flint, then the player has to collect gravel in huge quantities for flint, which is awkward if they only wanted a little bit of flint. This is why I think the villagers should duplicate the processed items:
3 gravel + 1 emerald for 10 flint
3 cod /salmon+ 1 emerald for 6 cooked cod/salmon