I can understand why you'd have mixed feelings about skills, but opposed to niche protection? Could you elaborate on that, 'cause I honestly can't wrap my head around why you'd oppose niche protection unless you were also opposed to classesHere's the elaboration: I loathe niche protection. It does terrible things to your game, your adventures, and possibly to your pets as well. It has no reason to exist, even in a game with classes. Perhaps especially in a game with classes.
But maybe we should be clear about what "niche protection" is, since when I first heard of it after 15 or so years of playing RPGs, I didn't have a clue what it could be; and after hearing an explanation, I thought "What the hell...?" It's like aliens came down from the sky and planted chips in some gamer's heads.
The theory of niche protection is that each character should have a distinct role in the group, something only your character can do, or that your character does best. Sometimes, niche protection proponents link niches to classes; other times, to MMORPG-style roles (tank, dps and ... healer? I think. Not really into MMORPGs.)
The general problem with that, from my perspective, is that old-school characters are supposed to be able to try anything. Telling a player, "No, you can't try to force the lock on the door, because that's the thief's job, and you might make him cry" seems contrary to the spirit of telling players to make decisions based on the situation, not on your character sheet.
Furthermore, classes and characters in old-school games often have very little detail. You are not supposed to differentiate your character by picking a unique race/class/ability score combination, but by, you know, playing your character differently. Old school play expects that there might be two fighters. Or three. Or maybe even ten. How do you protect that many niches, in just the area of combat? What if two people want to play Magic-Users? Do you tell one "No, the other guy might cry"? Do you force them to take different spells?
The more I think about niche protection, the more I realize that it causes all the evil in the world. Or, at least, the gaming world. You need more classes, because you need more niches. Or you play with smaller parties, so that you only have one character per niche. In which case, better design adventures differently, so that a party of four won't find it too tough. Can't have hirelings! They stomp on someone's toes! Classes have to be overdesigned, because you have to try to make each one distinct. You need skills, to help make two fighters distinctive. Feats, too. No randomly-rolled characters, because what if two players roll similar stats? Better make the ability bonuses finer grained, too.
Niche protection is the Great Satan. Go forth and stamp it out.