If anyone dare give me an iron bow again I'm gonna snap it.. or whatever. melt it.
Why? What's wrong with an iron bow? Or glass bow for that matter? It's not like the whole bow is made from that material. Or am I viewing http://www.uesp.net/wiki/File:OB-items-Bows.jpg image wrong?
Edit: Forgot to answer OP
I think maybe
some things should, if not require, then at least be made available, by means of "designs"/"enchants"/"recipes" you find. I.e. for smithing, you could find a certain cool looking design for a sword, which you can create from material of choice, but you couldn't come up with it before you found it. Similar for alchemy, mixing even the right ingredients may fizzle until you get the instructions telling you
how to mix them correctly. I'm a bit lost for enchanting. Maybe you find prebound souls giving additional power maybe?