Well, if it is anything like the iPod or iPhone, it is pretty easy to replace the parts. There are multiple vendors selling parts for them (some parts better than the original). The "closed" battery should be the least of people's issues. The replacement is the same price as another laptop battery and you get a whole new iPad.

For example, at some point, I am going to replace my iPod's (5th gen) HD with an SSD and there are multiple vendors and video showing how.