Technically you'll always be weaker than a luckier character due mainly to the decrease in critical hit chance. This will affect all players to some degree, but it's nothing you can't compensate for.
I played one game on very low luck (but not that low), and the differences in combats compared to my run before that where I had luck at 6 was definitely noticeable. Ranged characters both times. I think the biggest difference is due to not being able to pick up Better Criticals, More Criticals or Bonus Ranged Damage. That and the Sniper perk, though obtainable, is useless without high luck.
So ranged characters are definitely disadvantaged more, plus critical failures tend to be deadlier with ranged weapons; however, the lack of better criticals will have a noticeable effect for all characters. Of course, the Slayer perk makes up for that somewhat.
There are other perks you'll miss out on, but they're probably not ones you've even thought about taking anyway.
There are some good weapons, you can easily mix it up with anyone using ranged weapons only - provided you close the gap first. Melee weapons also tend to be faster to use than ranged weapons, with unarmed being faster still (for the punch anyway, which includes power fist and brass knuckles).
Since you can get lots of free unarmed training, I'd go melee first, then unarmed - though it can be tempting to drop points into unarmed just to unlock all the extra combat moves. Weapon details are on this wiki:
http://fallout.wikia.com/wiki/Fallout_2_weapons One more thing - I think while low luck will decrease your chance for most special encounters, I think it increases your chance of getting bad ones - at least the "special" bad ones. Do you like dogs? ;)