Unfortunately, as far as I can tell, the implications of adding [SHARP] to stones means an automatic 50% (Edit: I...think? I'm actually not sure, I haven't looked into it yet because I'm lazy). I did it mostly because Obsidian, for me, tends to be fairly rare, especially when compared to other stones that were commonly used for weaponry. Nearly every world I've gen'd has a fairly high concentration of flint.
I was also especially annoyed by the lack of [CAN_STONE] items due to the fact that spears, maces, and basic (if highly breakable) axes were all possible and somewhat common to our ancestors. Makes sense that the Dwarves of all races would know how to use it. Currently I haven't added [CAN_STONE] to the basic mace yet, but I might shortly.
So far I've had no problems navigating the Craftsdwarf shops with the amount of stone weaponry available, it comes out to less than, or exactly at, one page worth at best.