I like to give old D&D shit for apparently throwing random ideas for rules and mechanics at the wall to see what sticks, and then keeping some around for decades even though apparently nearly everyone ignores them. But I do really like the idea of starting character creation with randomly rolled attribute scores and players then having to work out a way to turn that into a character that is fun to play. There are plenty of character types that can make for great additions to a party of adventurers and produce interesting situations in play with their peculiar traits, but which you would never choose to make when creating stats from scratch because it would obviously be an inferior choice.
I don’t usually believe in forcing the players to their enjoyment (strange, this German expression doesn’t seem to exist in the English language), but not letting the players choose their character attribute scores is one thing where I make an exception, if the rules system for the campaign is suited for it. (I wouldn’t do it with D&D 3rd ed.) But there really is the chance to get a character with just crappy attributes, or which is really only suitable for a character type the player just doesn’t care about. Which is why you almost always have some limited degree of customization for the rolled attributes.
In Dragonbane, the rule for creating attribute scores is 4d6 keep best 3 in order for six attributes (the same as D&D, it’s a Fantasy Heartbreaker). Players can then chose to switch any two of the numbers with each other to have a bit of flexibility. Once the attributes are set, they determine the starting rank for all 30 skills. The players then select 6 skills from a list specific to the characters profession as trained skills, and between 2 to 6 of the remaining skills depending on the character’s age. Trained skills have their starting rank doubled.
The Houserule: Players can switch two of their atrributes with each other for free. For each additional score to be moved, the character looses one of the age-based free trained skills.
A player who makes an adult character (6+4 trained skills) and wants to rearrange four of the rolled attribute scores would have only two free trained skills to select after picking the six profession-based trained skills.
This seems like a decent trade to me. With Dragonbane’s skill and advancement system, giving up trained skills in character creation means that you’ll have a somewhat slower start by starting with fewer skill ranks in total, but you’ll have more starting ranks in the main skills for your character concept. And doesn’t close off any future developments for your character. But just one trained skill fewer can easily cost 4 or 5 skill ranks in total, which is not insignificant.
If you really want to play a fighter even though your Strength and Agility both came out really low, you can. But placing a price on it might be an incentive for players to take some time to consider to perhaps create something interesting and fun from the weird attributes they rolled.
I like your concepts a lot. What are the penalties for being old age?
Young gets 2 free trained skills and a bonus to Agility and Constitution.
Old gets 6 free trained skills and a bonus to Intelligence and Willpower, but a penalty to Strength, Agility, and Constitution.
Since attributes determine your starting rank for all your skills and having skills trained doubles the starting rank, young and old age both make you loose and gain some skill ranks. So it’s hard to really say if playing a young or old character will make a character stronger or weaker than the default adult. It would depend on what stats you rolled and what profession you want to play. (And as such, young and old age really only work when attributes are rolled instead of picked.)
Though a bonus to Constitution means young characters get more hit points, and a bonus to Willpower means old characters can cast more spells or use heroic abilities more often.