So do I understand that this is a thread put all the suggestions so far seen, around this matter? (It looks like it, these being ones commonly come up with before.)
If so, I think you missed one particular refinement of the idea, that I agreed with (if not mentioned), myself, at some prior time... Skill does matter, and affects relatively how much of the mined-out stone tile ends up as dust, gravel, rubble or chunks (in ascending order of size, descending amount of quantity, and greater skill needed for the latter than the former). BTW, I'm using 'chunks' instead of 'block' or 'slab', as these have other meanings in the game, but I'm talking large here. As large as existing 'raw mined rock' can be assumed to be.
Maybe you get a choice of whether to 'blitz' the rock (pulverise it, nothing but dust, whether that causes cave-in-style 'bad air' or just abstracts away) or to try to quarry it to one degree or another (slower, but with a skilled miner you get your necessary 'chunks'.)
And while you need rubble-or-above for trinket-sized rock-crafts, you need chunks for furniture-sized rock-crafts. Which is not to say you can't create a load of trinkets from a single chunk-sized piece. Rubble is only really usable as building material (filler, to bulk out the rubble/chunk walls, but maybe on its own for road-surfacing, at least. But maybe more use if concrete-style tech is developed, which the Romans managed to do so might be considered available to the 15thC-ish level of tech that DF is sort of pegged to... although I expect full-on tarmacadamming of floors to be only available through modding).
Any no-skill miner can (slowly!) bash an opening, of course, dust effects allowing, but to extract the increasingly usable non-dust mine-product (in 'quarrying' mode) takes skills with the pick, and has a time penalty. Although a legendary miner could probably carve out the raw materials for tables through the hardest granite at a higher rate than a novice miner manages to just open up a similarly sized room in a talc layer... If/when lack-of-prop/support-pillar cave-ins get reimplemented for larger open areas, I also reckon the skilled miner could eke out a larger area without danger.
I don't know how minecarts are going to work, but you might only be allowed one or two 'chunks' per minecart, compared with a whole heap (i.e. a number of basic units) of gravel. Not just weight-wise, but also due to size constraints. Unless the carts are flatbeds, in which case the opposite might be true (pile more slab-like chunks on top, but a gravel pile is likely to fall off unless it's a small pile. But I see hints that there could be the ability for different carts (primarily material?) possible to Mod, at the very least, so having flatbed and 'bucket-style' carts as separate and better-for-their-own-specialism rolling stock might be possible.