I understand the need for progression; no player should be able to just don scale armor and effectively use it. However, if the skill tree in the MMO is anything like LiF:YO.... well that's just unbalanced.
I don't understand how a player needs to understand how to use leather armors before they can use crossbows. It makes sense to understand how to use throwing weaponry, and then crossbows, but armor? What? Another example: in the current iteration, you need to know how to handle a war horse before you can wear chainmail armor. The logic behind this is lost on me, I don't understand.
I think the best way to balance this would be to place armors into a defensive skill line, and weapons into an offensive skill line. So cloth armors and militia weaponry would be the starting skills that need to be increased, and then from there, branch out into their respective paths. Handling horses and horseback combat, naturally, in their own skill line as well (first, you need to know how to ride a horse before you start swinging your blade, or shooting arrows while mounted).
For instance, Militia Weaponry would branch into one handed weaponry, two handed, shields, ranged, etc.
Cloth armor would branch into leather and scale, and plate would branch off scale, with chain branching off of leather, or some other form of branching.
As it stands, it doesn't make a whole lot of sense (to me, the player) to incorporate offensive and defensive skills into the same path, especially if they limit what you can do.
Skill lines should represent knowledge gained in that field, so ranged weaponry should all be in a single skill line, and medium armors should be their own, two handed weaponry in their own skill line, and so on.
Do you believe the current skill system, as far as combat skills are concerned, needs tweaking?