If we're assuming the Theme/Background dichotomy still applies, then I could see crafting working in either system.
For a background, it's a relatively trivial thing because mundane crafting generally only applicable for a short duration of a character's life. Sure, there are ways to expand the system - exotic materials, for example. However, in every system, magical items are the stuff that matters once you gain a few levels. So you can craft basic stuff, maybe you get an item for free, it's relatively minor because it's not magical.
I could definitely see it as a Theme (or feat grouping, if you will) in that perhaps different equipment groups require different feats. Or perhaps you can focus on a group and you improve the outcome of the crafting. Maybe it could even be something like a watered down version of an Alchemist.
Personally, I've never found any of the mundane crafting abilities so over-powered that they couldn't be given out as backgrounds, but that's just me.