The IP restrictions were originally put in place to prevent multi-client/afk players.
Since then, we've had a number of requests to lift it, so friends and family could play from the same household. We understand and recognize that desire, and have been considering options since.
For PvP it is important that ever player participate, otherwise it can greatly change the strength of a team and we want it to be fun and competitive.
For dungeons, we also wanted it to be similar, but because it is not competitive, we've allowed up to 2 connections from the same IP.
A solution we have settled on, but have not yet begun any development towards, is to make it so Premium Status are not counted towards IP restrictions. Yes, paying would allow you to connect multiple clients from the same IP. Please do not mistake this for being a point of greed or business, while it would be business beneficial, it is because we feel that a paying user would be less likely to abuse it in a manner that causes the intention of participation and affect the competition of PvP, or hinder the success of a dungeon run. We feel that a subscribed user to our Premium Service, would take advantage of it with a friend so they could play together. Undoubtedly there will be those who will use it to take advantage of the ability to have multiple connections, but in the end they are paying to suffer from the community's ability to recognize when someone fails to participate and costs them the match.
A short term solution we're going to do, until we're able to full implement this idea, is we will be allowing up to 3 connections per IP, within the dungeons only, to assist with a few families that have approached me on the subject, so they can enjoy playing together.
We won't be changing PvP because we still feel there's a high need for participation, and for those who currently use a proxy to bypass the limitation, as long as you aren't being reported for being afk for doing so, we are willing to give some wiggle room for now so that you can play with your friends or family on the same line. But once the premium feature is implemented, we'll ask that you not do so. It's not for us, more than it is for you and for some methods of account authorization for support related matters.