A grinding block primarily for leaves

Edit: or potentially further use for the grindstone, but I would like to be able to use hoppers with it tbch 

I propose some kind of block that will take the input of blocks that can have some other block some out of them, and will spit out the block that is supposed to come from that block For example it is ofcourse allot quicker to strip a tree of it's leaves using shears but then still have to 'mine' them properly to get sticks and saplings, so this block would allow you to just strip the leaves and put them into this block for it to then output the saplings and sticks, I saw a suggestion for a block that grinds stone into gravel, which could potentially be another use for the block I am suggesting (to be clear, I don't think a block that just grinds into gravel particularly useful on its own hence the new post giving what is in my opinion a better primary use for such a block given the abundance of gravel in the world) Could also put gravel in to produce Flint tbf? Potentially take a hopper chain out of the proposed block with an item filter for gravel that leads back into the input so you could input stone and run it through twice to produce Flint