Well, I've just gone-off on a big tangent about what effects I feel different stats should have had in Fallout 3 in order to make them feel like they have some more substance, but what does it all mean? Basically, it means that choosing the SPECIAL stats at the beginning of the game feels more substantial. As the game currently works, no matter how you modify your SPECIAL at the beginning, nothing really changes. There's little penalty for lowering a stat except for Intellect and Luck (and even Luck is debatable), and little bonus for maxing-out any stat besides having a nice and shiny "10" to look at.
Below is a little run-down of the more common builds of characters, the stats they'd like want to opt for, and what they would lose if they sacrificed other SPECIAL points to get those stats.
As the game currently works, a Stealth-based character basically plays the exact same way no matter how you build his SPECIAL. A little more carry weight here, maybe a little more health, but nothing actually changes what the character can do. With the listed changes however, a Stealth-based character would have a little thinking to do towards how he plans to play the game, and what he's willing to sacrifice to get the points he wants.
As a Stealth-based character, Agility would be hands down your favored stat. When crouched-down to sneak, your movement is slowed slightly, and having a higher Agility would compensate that a little. A melee-based sneaker wouldn't want to sacrfice anymore in Strength than he has to, though that's already the case. Most likely he'd tap into Charisma to gain access to a few more points that he can spread about unless he wanted to be a "Jack Sparrow" style of character, sneaky and suave. Perception would gel nicely with the theme of stealing anything he can find, especially if Perception were to play a roll in Lockpicking.
With less Int, hacking computers wouldn't be as easy, and they'd be able to repair their gear just shy of perfect. Without much Endurance, there would be more risk in popping Chems, especially if the addiction penalty was made worse. Luck would be a matter of personal choice, you get free crits anyway when making a Sneak Attack, but you might want the higher Crit chance when things get less sneaky, and you might find that slight bonus towards everything done to be attractive as well.
Heavy Weapons Guy
TF2 references aside, Big Guns in Fallout 3 are severely gimped beyond the repair of just modifying the SPECIAL stats. Simply put, the big guns don't hit much harder than the small guns despite having a lot of penalties tacked onto them. But that's a topic for a later BaBF. As a Big Guns focused character, your choices would come with similar drawbacks to what's listed in the Sneak character. The difference being that you would favor Strength and Endurance.
Now, granted that a character focused on Big Guns will already do that to some extent, however a high endurance would only be taken for that slight boost in the starting Skill Points, after that it doesn't actually do anything to help the character use his bigger guns. In Fallout 3, carrying a big gun comes with a movement speed penalty, so obviously you're going to want to change this if you're focus will be on Big Guns, thus you'll favor Endurance for lowering that penalty, perhaps even eliminating it completely when Endurance is maxed.
Strength is currently nice for a character of this build because it increases your weight allowance, but careful planning would probably make it just as possible to play an effective Big Guns character with a Strength of 1. That is, of course, unless Strength played a role in effecting the accuraccy of the weapons. Not to mention that as a big guns user, you'll probably want heavier armor, which under the assumed changes comes with a required level of Strength.
This build would make similar choices to the previous build, but for different reasons, and with one key difference. They would opt for Strength for harder hits, and a little Endurance for the sake of a more effective block, but unlike the big guns user, Agility would be more important for a melee-focused brawler. This is both because it would give him a better chance to dodge other melee-based characters, and because it would add to his movement speed, allowing him to close the gap on ranged enemies a little more quickly.
He would likely end-up sacrificing a lot in the other stats to get this, most likely Int and Charisma, possibly a little into Perception as well, especially if he wanted to sneak a little crit into his hits with higher Luck. This would probably be the most varied style of character build from player to player simply because there are 4 really good SPECIAL stats for a Melee-based character to take under my changes, but not enough points to get them all really high without a lot of sacrifice.
Some people would focus on Strength and Luck, giving them the hardest hits in the game, others would probably favor more Agility or Endurance to give them a little more survivability, not to mention allowing them to pop chems more effectively.
High Perception for better accuraccy would be the first must with a Sniper-focused character. Beyond that, there's a lot of breathing room to make this another flexible build where different players would favor different things. A full-on Stealth/Sniper who plans to kill as many enemies unseen, close-up or long-range, would favor more towards Agility. If you want to pop some chems when things get thick, you'll want more Endurance to tough those situations out. Maybe you want high Strength so you can swing your melee weapons harder to make your character like the TF2 Sniper.
And thus, with a few changes to how the SPECIAL stats effect different things in gameplay, suddenly it's a bit more interesting to consider your options when planning your character build. Do you sacrifice some accuraccy to make your character a little more sneaky? How important are critical hits going to be for your character? Do you want to repair your gear more effectively, or will you allow NPCs to maintain them more? Do you like to use Chems, or are they mostly just a source of extra caps? Every answer modifies how you might want your character to be built.
As the SPECIAL is currently set-up though, there's little change from character to character. You can carry more, or you have more health, but really the SPECIAL stats do little to change how any given character is played. Even Agility, arguably a good stat for a VATS-focused character, feels bland when you consider how little it adds for AP. Meanwhile stats like Int and Luck feel a little over-powered as stats since the former gives access to Skill Points which actually matter, and the latter gives Crit which can't be gotten anywhere else.
Still on the schedule for Building a Better Fallout: Tag! You're it!, Undynamic World, and A Little Off-Balance.