It's obvious...you need to do something about the loss of the subscription center.
People are pissed. And lets face it, It's not like you can't restore the page file (or write new code for it) you just don't want to. Maybe you need to come up with a workaround that can give users the same info...but something has to give (that something is you 'xtube.com'.)
We are very sorry for all this inconvenience the new layout of the subscriptions has caused. This was not our intention. We try our best to improve and keep the site enjoyable to our customers.
The ability to subscribe to tags has now returned to the subscriptions. You can subscribe to tags here: http://www.xtube.com/account/my-subscribed-tags