Indeed. Dressing like a lost and poorly equipped civvie in the desert should get you attacked, but dressing like a deadly high-tech soilders should put some weak raiders off. They should also take your level or skills in considerment, I mean, you can see if that guy there is looking inexperienced, clutching his gun in a weird way, looking nervously in all directions, or if he looks like a stone-hard, experienced killer. But only a little, they'd look more on your party's equipment. DT and DPS and such.
Then I'd also like something like "general reputations". Not a reputation for single factions, but a reputation that most people know about. If you kill alot of innocents and/or unarmed, you may get the general rep status of "Killer" and people know that you are a dangerous person. If you are the one who always start combat, that is, if you shoot people before they are hostile, then you get the general rep status of "Unpredictable" and employers that would like to hire you may get a bit nervous about you because you might just shoot them. If you do many quests, but not in the normal "Of course I help you for free"-way, but doing it merc style and saying "300 caps or I walk" then you gain the general rep status of "Mercenary". People who need jobs done will want to contact you, I dunno if you should be able to gain "Good mercenary", "Bad mercenary" and "I'm-just-in-it-for-the-money mercenary" rep statuses, to be able to get different merc jobs. Bad mercenaries of course get jobs to kill some people for your employer, and the good maybe escort a friendly caravan. The third version there is known to do every job aslong as it pays good. There'd be alot of other "general reputations" that you can get aswell, that won't only go for single factions. People would be like "I've heard what you did for those powder gangers, and I need a man like you to do a job for me". Maybe this could replace the flawed and unimportant karma system. Instead of good or bad karma you'd get good or bad general reputations. That would also make a little more sense in how the wasteland inhabitants hear of your good or bad deeds, whether anyone saw it or not (like blowing up Megaton, no one saw you do it!)