Small Frame

Small Frame is a trait which appears in Fallout, Fallout 2, Fallout: New Vegas, Fallout Tactics, Van Buren, Lionheart and J.E. Sawyer's Fallout RPG.

Fallout and Fallout 2
Originally you get a +1 bonus to your agility, but your carry weight reduces to 25 + (15 lbs. x your strength). It should be noted, that you can redistribute the point elsewhere by simply deducting AG value. But of course, your base minimal AG is risen to 2 from 1.

Value controversy
There are two opinions regarding usefulness of this trait:

First group of players thinks that this trait may indeed bring advantage,but brings a bit of trouble yet only in early part of game. Because you can hire Sulik pretty early, you can offload a lot of weight and gain one additional point to redistribute freely.

However, the second group of players tend to question its usability. Because of the points mentioned, small frame is rendered useless.
 * Because this trait mainly affects strength, and strength has basically only two uses in game: max load weight and weapon handling clearance, so taking this trait efficiently reduces strength (as in carry weight use) by one point, making difference only to gun strength requirement.
 * Maximum strength requirement for weapons is 7 (normal miniguns), with 5 being minimum for guns.
 * Strength can be increased by 6 points in-game permanently, with advanced power armor giving instantaneous +4, requiring no leveling or fighting. So, already with base STR 1 and suit you should be able to handle basic guns; and with base STR 3 - every gun possible.
 * Small frame greatly reduces carry weight, up to the equivalent of minus one-two point(s).
 * If you want to handle basic guns, you need at least STR 1(a minimum). With STR 1 and small frame, you barely can pick-up armor.
 * If you want to handle all guns, you need either STR 3, or STR 1 + 3 other improvements (brain alignment + gain strength perk + strength upgrade card). Plus advanced power armor. Tagging small frame with STR 3 also reduces carry weight to high degree (~ STR 2).

So, why not just remove the point from STR, redistribute the point elsewhere and leave space for another trait?

Note, that both methods require knowledge of in-game world, so the final choice of usefulness of this trait is highly subjective and is left to the player and his own play style.

Fallout: New Vegas
Due to your small size, you have +1 agility but your limbs are more easily crippled (25% extra limb damage). This detrimental effect can be nullified by taking the Adamantium Skeleton perk. Overall, just taking Intense Training for agility is a more efficient option than taking the Small Frame and Adamantium Skeleton combination. You cannot gain Adamantium Skeleton until you reach level 14, but Intense Training can be taken at level 2. The bonus from Small Frame is more detrimental early in the game due to the lack of good armor and healing supplies. By the time you reach level 14, you likely are not hurting too much from the negative aspects of this trait to be worth taking a perk to negate it. The Tough Guy challenge perk, does negate most of the negative effects of Small Frame without requiring you use a level up perk slot. Most people, even with Small Frame, do not end up getting it because it requires getting your limbs crippled 50 times. This trait is not recommended for Hardcore Mode, due to the fact that you cannot heal crippled limbs with Stimpaks; rather, you must use a doctor's bag or visit a doctor to heal crippled limbs.

Fallout Tactics and Lionheart
You are not quite as big as other people, but that never slowed you down. You can't carry as much, but you are more agile. You get a +1 bonus to your agility, but your carry weight is 50 pounds less than normal. Feralkins may not take this trait.

J.E. Sawyer's Fallout RPG
You are smaller than average. It's hard for you to carry heavy loads, but it's easy to avoid the lumbering giants of the wasteland. -50 to carry weight, +2 to evade.