If you want your shins covered, wear greaves.
Generally, I figure that dwarves are pretty set in their ways. Dwarves make dwarven items because they're dwarven, and the items dwarves make are dwarven because dwarves make them.
Bumber, you might have missed that part there. What I was getting at is that regardless of how effective high boots are compared to vanilla low boots (yay extra shin protection), dwarves are dumb enough and stubborn enough that they aren't liable to suddenly change their mind just because one of their own decided to make an artifact.
As for clothing, it's mostly just there as a flavor thing and wouldn't matter much whether or not your dwarves could make it. The exotic versions (frilly boots, jagged robes, rectangular shields, or whatever) again are just a flavor thing and would be redundant. Given what I said earlier, it definitely could be argued that dwarves could (and maybe even should) make different items without those items being "undwarven." In fact, a high boot artifact is just as dwarven as any other artifact, but like I mentioned, it's more quaint than it is -useful-.
With weapons, it's a bit trickier to handle. Many of the exotic weapons are either too big for dwarves to reliably wield or (like with clothing) are exotic because they have a silly adjective (long crossbows, curved war hammers, etc) and don't seem necessary. I wouldn't be opposed to dwarves learning how to make different stuff, especially once they can reliably wield bigger weapons, but I do enjoy the idea that they can be dumb and stubborn, even when it's to their own detriment. It also helps make some of your quaint artifacts feel a bit more special when they -do- show up (especially if they're both quaint -and- practical).