Craft is problematical, just like multiple knowledge skills. If I want to make swords or armor, or repair the cart, or the castle before a seige, I have to have loads of skill points all over the place. No one takes craft for that reason in my games, preferring to just buy an NPC.
Also, craft is a non-combat action, so why waste space on a combat character's sheet?

Linguistics is a skill: every rank means a new language.

Why not have Craft be like Linguistics: every rank is a new type of object you can make. Armor, weapons, seige engines, alchemical compounds, seamstress/tailor, ship building. All these things use scientific principles in the real world, so if I'm good at building other stuff I'll have less basic stuff to learn when I turn my hand to it.

Some people are just good with their hands, like others are polyglots. Dwarves and Gnomes can just fix stuff, elves make all sorts of goodies. A wizard could make a golem, a staff, a ring, a flying carpet, but doesn't have to be a master at all these things to do it. I can make cookies, with skills related to that; why shouldn't making soap or mixing paint be aided (aside from synergy bonuses) by my skills there? mixing is mixing.

(Dang board monster! Stop eating my posts!)

What I was trying to say is that I agree. I'd say every 2 or 4 ranks is an extra Craft, not every rank, but essentially, I agree.

I also think Perform and Profession skills should work this way.

I've thought about doing something similar with Survival. Each rank gets you another environment - jungle, forest, mountains, urban, etc. Not exactly sure what would happen if you tried to use Survival in an environment you didn't have, -2 penalty maybe?

It also kind of works with Ride - a new kind of mount with each rank.

It strikes me that anything like this would work best in a hybrid skill system with only 3 or 4 ranks, otherwise you'd eventually get 20 different mounts or environments or crafts or languages, etc.

Also, craft is a non-combat action, so why waste space on a combat character's sheet?

I think we're on two completely different levels of gaming if you regard Craft as a waste of space just because it's not a combat-related action but I'll give it a go.

First, I don't really get your point honestly. What you're proposing is already possible. Want to be a tailor? Put one or two skill points in that, cross-class or not. At the next level, maybe you want to dabble in weaving? Well then put some points in that too.

If you mean just putting points in one craft slot and thus gaining points across the board on all those related skills, I can't say I like the sound of that cheesey idea.
I encourage my players to take craft and profession skills and many of them do. By excelling at a few of these, the characters grow and that opens up all sorts of rping opportunities like owning a popular brewery, making a beautiful piece of jewelry that starts a fashion trend or impressing the local noble with some fine cooking. The idea of the 'jack-of-all-trades, master-of-all-trades' takes a lot of the fun out of learning and reaching for these goals since you can do everything. How is that fun?
And I really don't think a seamstress falls into the same complexity and skill level as a shipwright, that's apples and oranges.

I dunno about that.

Thing is, Perception (spot and search, etc.) and Stealth (hide and move silently) are combat skills. Or, at least "right now" skills that have an effect in-game. they have a DC that is right there in-game.

Craft doesn't. There are feats for making magic items, but why do we need one for making armor? Or baskets? Or alchemical stuff? Why not just make them level-dependent like the item creation feats? It's not stuff you use in an encounter, and the GM is likely to just say "okay, you make three suits of armor; or not, because I'm a jerk"

There's no chance of failure: anything important, the PC can just take 10 once they're trained, because they're not in combat when they make stuff. Why aren't they in combat? Because the game isn't happening, they're in-town.

So why waste ranks in Craft when they could be in Perception (or even cross-class in Stealth, for the fighter)?

Granted, a "I'm good with fixing stuff" skill *does* have an in-game effect. Like checking out whether a place can be fixed. Or disabling devices, or picking locks.

really, picking locks isn't a "thieving" thing, to be packed into picking pockets. I know a locksmith, and he's not a pick pocket. An artificer isn't a pickpocket either, and I wouldn't expect it of Gepetto (Pinocchio's dad). It should be a feature of the skill.

know what I mean?

All my characters (when I'm not DMing) have craft and/or profession skills, and make their own items, in their down time (and I make sure that the DM allows me to do that, and I allow my players to create things as well). I feel it adds to the "experience" of the game and makes it more fun for me.

I can somewhat see the point of the OP and others about it being nice if you didn't have to use multiple skill selections to create different items, but at the same time, if you want to play your character that way then take a couple of craft skills and have fun with it.

The other option that you have is to house rule it, and combine several like craft skills in to a consolidated skill that would allow the character to craft several types of items with a single craft skill or profession. A blacksmith for instance may be able to create armor and weapons along with the horseshoes and farm implements that he makes every day.

Hope this helps.

DJ