This is all part of the plan. It's a smart marketing technique. Offer something for free, let the client use the product for a while so they develop a dependency, then start degrading the product so the customer isn't seeing the same results, then ask them to pay for a new and improved version.
Subscription Nostalrius server incoming. Shoot, I'll pay monthly if their server works and i get permanent rested or double honor as part of my subscription.
That would be Illegal so I'm pretty sure it isn't that...I assume I know why it's happening thought. It's astonishing that they managed to come out with a perfectly working and very well bug fixed server a month before the competition. So, likely what happened is that since Nos never did a progress bar thing like Kronos did that they never even started working on the later raids until after they successfully stole the player base from Kronos, and now they're saving time and effort by working out a lot of the bugs on the server while it's live so they have more access to bug reports.