Right. I wholeheartedly agree that raising your mining and axe skills should help you raise your strength. And in the process of learning about Blue and Brown Way magic one would become more intelligent. And so on, and so forth.
But if stats become derived quantities based on skills, then the only way to get stronger would be to mine ores, swing axes, or wear heavy armor. That's fine. But what about when you start applying that to other stats? In order to be a very intelligent character, you would have to raise your Blue and Brown Way skills. A person who wants high charisma would have to raise Crystal Way, Dark Way, and empathy.
well, you're limiting your example to an extremely small sample of skills. this would apply to ALL skills, even those not yet developed. Hammering away at a forge all day could also improve strength or endurance, making alchemical solutions would increase int, etc. Even some combat skills could increase mental stats, ie. ranged would utilize will (i'm using will as the closest attribute to focus, which is necessary for an archer). You'd be able to build up your stats evenly across the board by choosing a combination of skills to develop.
but I think the point here is to limit a players ability to be maxed out across the board. I know we're going for an open character development system, and I think we can retain it this way, but a system in which every character eventually becomes a one man army is a faulty system for an RPG. Maybe i'm wrong, but I feel that forming a party of adventurers, each with their own unique skillset and attributes so that each player fulfills a crucial role within the party, is like the whole point of this genre of gaming. Cooperation, collaboration, team work, problem solving skills, being able to use the mechanics creatively to gain an advantage, etc. etc. That's what makes role playing fun.