This sounds like an interesting thread, so I thought I'd pop in with my theories. I don't really post at all, but I liked all the comments enough to want to share with you all.
First, I don't think he's the only ranger, just the only one that he sees, as there are a lot of people in the level 1 area. As he has said, archers are considered weak as compared to sword or melee fighters, while for distance battles, magicians are also more popular, since they can gain more powerful spells and they aren't caught by enemies' bloodlust senses. Rangers, in terms of stats seem to be the weaker of the classes because of this. However, in terms of solo battle, a ranger has both long distance (mage) and melee (fighter) abilities.
In terms of calling them useless skills, I think this is not true at all. Archery is all dependent on the level of your equipment for damage, which is why it's less popular than say, fire magic. Also, it is most likely poor until you work it up in level because your accuracy at long distance is so low, as compared to magic, which seems to home in on the target or take up a huge area so one is guaranteed to hit. As we saw, once he hit a higher level, he was much more accurate. The same goes with Wind Magic; it is not just for up front damage, at higher levels, it increases the player's speed, which when added to the Kick skill, can allow one to do ridiculous things like kick an arrow through a wild bear's skull. Speaking of Kick, it does not impart any moves, but it does increase any abilities that involve the feet and legs, like running jumping, and of course kicking; so if someone knew martial arts that used kicks, one could be dangerous. Stealth, which it was mentioned that most players believed to be a fleeing skill, is actually an incredible skill for the right class. Right now, if Earth were to increase his Archery even higher and make a better bow, he'd be an amazing assassin. Physical boost actually works great for a solo player who doesn't have anyone else to depend on, as it increases all physical attributes (strength, agility, constitution) instead of just giving you an increase in one particular thing (one-handed sword, punching, etc.). None of these skills are "great" or "powerful", but they do make for a well-rounded character who plays mostly by himself.
As for cooking, as cjk33 has said, they cover many reasons why it's not so popular to cook in Chapter 4 that makes a lot of sense. I also would guess that no one realized that food could also boost stats and restore HP and MP.
In the area of extra skills, I would guess that for every X number of levels you go up, you get an additional skill. Otherwise, you're stuck only knowing the skills you had at the very beginning of the game, and more people would remove their characters to make new ones, or create more farming characters.
I do have to admit to being impressed by the Eagle Eye skill. Not only can you search for monsters, you can forage with it as well. If I were interested in making money, I would not take cooking or apothecary, but increase Eagle Eye, forage the heck out of the place, and sell your findings to all the cooks and apothecaries. You wouldn't even have to try to identify if you didn't want to; just make a grab bag - 25 random herbs for 50 gulor.
Okay, I think I've vented and rambled a lot. Thanks for your patience.