Hello, new to the forum but have been playing DF for a while (and searching in here every now and then).
My opinion on this metal issue is mostly "Like it!" Too much variety in a small space spoiled the realism for me. The current situation is not, at present, ideal, but I'm hoping (without evidence) that since it's part of the Caravan Arc that'll mean setting up regular trade caravans with other civs (or forts) to bring in sufficient supplies of what rare material they have for what rare material you have. However, we aren't there at present but I can live with that. At least it's no more "WHat's the point of anything other than steel?"
The only change I would like is for when you do find metal for it to be in a single large vein (or two). It doesn't have to be much more than three or four tiles wide, but should extend numerous z-levels. Then it'll be a great cheer to find, and I could start having realistic-looking mining operations, with vast stopes and multiple adits if it's on a mountainside instead of a few random tunnels snaking about.
Not found any coal yet. That's a problem; I'm rapidly getting through trees, and I don't want to have to dig down to the magma early in the game. Does "metal" in embark include coal?
Incidentally, my first discovery of "shallow metals" contained lots of haematite, and sphalerite when I went below the sedimentary rock.