To follow up on a point I made in my previous 'Introduction' post, there is a fundamental difference between the way old school and new school rule-sets approach a character frameset.
When I first started playing RPGs starting with 2E Dungeons & Dragons, I had no real concept for how the game should be played. I understood fantasy tropes to a point so when it came time to create my very first character, I tried to come up with something 'cool'. Prior to me ever playing or understanding D&D my uncle Bob would tell me about how he and my cousins would stay up late at night when they were younger and play a game with dice and graph paper. He had a character named 'White Cloud', a reference to his imposing stature and tendency to wear white shirts I would later find out. When I made my first character I named him Gray Cloud as a tribute of sorts. I assumed my uncle's character was good, but since my character was going to be a chaotic neutral thief, 'Gray' seemed more apt. Gray Cloud wore a black trench-coat lined with daggers on the inside. He had a preference for throwing daggers, or so I envisioned.
Since this was 2nd edition, there was no 'character builds' to look up. I simply had his attributes and some of the Thief ability percentiles (open lock, move quietly, etc.). When I joined the party the rest of the group were of varying levels but I was the squishy level 1. I could count my hit points on one hand. My friend Bruce was the DM and happened to roll his dice in front of us for the most part. In my character's very first battle, against an ogre, my strategy of going for the backstab was a faulty one. The ogre didn't like my backstab, not one bit, and proceeded to attack me. Natural 20, in front of everyone. Bruce was ruling a natural 20 was double damage, and with that, Gray Cloud poofed into a very big puddle of blood. Max damage was rolled. Oh dear. Bruce felt bad but hey, it happens. I rolled up a new thief, a chaotic good one (karma?), presented myself happily to the party, and was accepted. This character even got Gray Cloud's old stuff. I liked that trench-coat.
No what does that experience have to do with my original point? Well consider that experience. I created a character with a concept (trenchcoat wearing knife thrower), he indeed had a bit of personality, did not use a 'build' as modern gamers would be used to, and he was unceremoniously obliterated in his first combat.
Had this experience been done in a modern ruleset, such as 3.5 D&D or Pathfinder, I would have been worrying about what feats and skills might have fit the character concept or abandoned it entirely to use a good 'build'. I think the 'build' mentality comes from the fact 3.x plays well with a video gamer attitude and those who play WoW or Diablo will know that good 'builds' are the key to victory.
Modern gaming also seems to support the idea (at least PF does) that the characters should succeed because they are the player characters, the heroes, for which the story and world revolve around. Granted this is usually left up to the DM, but the feeling I get from most others in the hobby who play PF is that is the standard. A character is something precious with a detailed back story and likes/dislikes planned out far in advance of the campaign starting.
Of course, when such a character dies, the player is quite upset. All that work for naught. What if the solution is to just create the character and let the character evolve during play? These days, when I roll a a character regardless of ruleset, I give him one or two personality traits and go with it. As the game progresses and it turns out my character has some survivability, maybe I can expand his personality. At low levels where characters are fragile, I think it's best to leave them as mostly blank slates, as I like to think I did for Gray Cloud.
I greatly enjoy the concept in Old School Rules that the PC's are just people, somewhat extraordinary, but aren't really heroes just because 'they are PC's and that's what PC's are'. They BECOME heroes over the course of the game. I've always been irked by players who create characters who happen to be 'royal heirs' or 'have an important destiny they don't quite understand'. Really? I'm sorry that pitfall was your character's important destiny. I guess it's a matter of preference, but my characters have always been nobodies who just MIGHT achieve greatness. Might. Probably not. But might.
I think this is where the idea that Old School is typically more gritty than New School. The Old School of Thought can maybe be a 'realistic' world where people die and so often, considering the dangerous circumstances of adventuring. New School of Thought is that the game is the player's fantasy of heroics, where everyone gets what they want or close to it, in terms of storytelling. I think both schools have their place and use. This is probably why I will continue to play both Swords & Wizardry and Pathfinder.
Okay, that's enough rambling for now. A lot of this is anecdotal and somewhat opinionated, I'd love to hear others' thoughts.