This trait is useful, as it is unlikely for even a combat-oriented character to use more than 3 of these skills, and in all likelihood only 2. As such, 20% is "lost" while at least 45% (speech, barter, and doctor) is gained. In Fallout 2, first aid is mostly useless as one can wait indefinitely. This is not the case in Fallout, as all 60% of this is useful. One may also tag their most used combat skills, negating the initial loss and increasing by 5%.
This trait will boost your social skills, while lowering your weapons skills. Although this trait seems like it would only be preferred for a pacifist style play, it is not a bad choice for aggressive players either. Most players will usually only use one or two types of weapons, allowing the trait to enable them to use all of the boosted skills eventually.
This trait gives twenty five extra points to skills most characters make general use of, while only taking away five or ten from the main combat skill you use. This equates to more or less a level and a half worth of skill points added to your characters maximum skill point potential.
The following is based on Lionheart and is not considered canon.
Your combat skills start at a lower level, but barter and healing rates are substantially improved. Barter gets a 25 point bonus. You also get a negative 5 point modifier to starting melee combat skills (one-handed, two-handed, and unarmed).