Very nice.
I'm playing around with an entrance somewhat the opposite of what you have. I dig out a deep pit, however leave a centre column (and a wall-bridge to this column), then spiral a staircase down around that.
I am also using similar moria-pillars for my grand hall, however my grand hall serve only as an entrance. In my current fort, I have 4 rows of pillars (maybe 10 tiles apart) by 4 rows of pillars going a planned 8 levels up. They start as 4x4, however they are 2x2 whenever they are not in contact with the floor or ceiling, so they get a sleeker look if they're ever visualised.
I have then added my own personal touch: When coming from the entrance, the second row of pillars running across your path are not as much pillars as they are fortification chambers, running all the way up to my barracks, situated above the grand hall. Similar to the regular pillars, they are sleek until they hit the floor, where they bulge out and form 2 levels of fortification that armoured dwarves can shoot/stream out of. With hatch covers on the staircase to make them completely unstormable. Unfortunately, I have yet to test this system as I accidentally embarked in a no-goblin area and I have too good traps on my entrance bridge to allow any kobold raids.
I like your workshop designs. I usually cram my workshops into as tight a space as possible to increase efficiency, but I might consider making genuine halls for workshops, similar to how I am beginning to make grander and grander designs. If a single section of my fort goes architecture over efficiency, there's no reason to hold back on the other fronts, eh.