I think the 15" drawer might be closer to 12" clearance, depending on if there were undermount glides or side mounted -- check with your cabinet maker.

I'm putting in at least one large drawer with a vertical clearance of 12.5". I've seen an example of a tall drawer with adjustable dividers. Half the drawer was pyrex pans on edge and in the other half of the drawer there was space for a tall stock pot with steamer insert.

I would rather organize my pans, especially the glass or ceramic ones, on edge than to pull them out of a nested stack in a shallower drawer.

I wanted to store my Cuisinart with the work bowl attached in a 15" drawer, but it wasn't worth a dedicated drawer for one item, so I put it on the counter. You can also put some larger items over the fridge. I have a stockpot in mine.

All my glassware is stored in a 4-drawer cabinet--three drawers of 6 1/4" and bottom of 9 1/2". There's a lot of room in there. My pie plates and rectangular baking pans are stacked. The only one that annoys me is the 9 x 13 pan on the bottom, but I usually use smaller pans for just us two. I have a few stacks of two, like colanders and smaller baking pans. Covered casseroles are stored individually in the drawer. I also have a set of nested bowls, but they would be stacked even if I stored other pans on edge.

I wanted to arrange those items (not bowls, but all of the square and rectangle pans, cookie sheets, etc.) vertically in a drawer, but the clearance just didn't work. Most of them reside in the pantry anyway, so just last week, I got a pegboard and now have those items stored vertically in the pantry and it is great - so practical not to have to move anything else out of the way to get at a cookie sheet or pyrex dish.