everyone from same faction should be able to buy things from the special npc, weekly quest should stay accessible to the legion owning the altar.
realistically speaking, the npc would be useless for non-geared people without the weeklies:P it's kind of a paradox, can't get geared w/o enchantment stones, can't get enchantment stones w/o gear.
Why would it be useless you ask? cos from my personal experience, lowly geared you don't get enough stellium just from sieges to buy the coupons.
bro I started playing aion 10 days ago I farm 120++ stellium each day and I play solo, when you in ally you get far less stellium ........and I'm not good geared I only have like 10 legendary parts only weapons on +15 other parts ancient I agree with AionIsLife everyone should be able to buy things from special npc not just 1-2 legions that's unfair personally I don't care for 1-2 ulti stones you can farm 2 ulti stones each day if you know what you do