One thing to consider when looking at subrace feats is that these are package deals, allowing characters to become heroic examples of a cultural ethnicity as much as physical phenotype. NPCs could take the feats, or they could amass the approriate qualities by other means, but the real focus in there design is what they will provide to players.
One of the tools used was weapon proficiencies. Weapon proficiencies are a cultural feature more often than a biological one. Sometimes they are logically required because a feat provides bonuses to using weapons of the included sort - in the same way that Practice Makes Perfect advanced tricks demand a forte level of expertise before you can use them. Sometimes the proficiency prerequisites are just there to firm up a theme - I paint images with mechanics at least as much as with flavor text, and usually the mechanics paint sticks a lot better with the concept meets the gaming table
. The feats could have granted proficiencies instead or requiring them, but then that would have taken up some of the aproximate 'value' a feat could provide. By making proficiencies a requirement, I know that the character is competent with any weapon that the feat might boost and I can save the 'value' of the feat for creating benefits more unique to that culture. If the resulting feat/package doesn't strike a cord for you, then it's just focused on modeling a different
culture than you might be thinking of, rather than doing it "wrong"
. 15 kinds of elves may seem like a lot, but it's infintesimal
compared to the number of kinds of elves that exist in the minds of gamers reading the book
. If you have the book, what you are looking at is my interpretation of many common themes confined within a balanced and playable rule set. I for one am very happy with the results because I think we've developed some good tools for showing some gamer favorites having weakneses or drawbacks that make sense, rather than brushing it all under a Level Adjustment rug. Are Spider Nation Elves as powerful compared to high elves as Drow are? No they are not. But then they don't play weird games with mismatched levels in a party to try and cludge the difference, either. Will the Spider Nation massage the "my character is better than yours" urge that Drow play to so well for some? Maybe- if you are looking for a particular flavor and theme rather than bluntly overpowered attributes and benfits. Level for level and feat for feat a Spider Nation elf and plain old high elf are in a dead heat by design
. And neither of them are particulalry better off than Joe the Human Barbarian. But all three of those characters are likely to appeal more stongly to one gamer or anther, and be able to contribute roughly as much at any gaming table where they meet.