Clearly it's not the first time Gardiner has had the question, but his reaction was a bit more focused:

'I know from the outside this seems like a fairly simple proposition, but doing this could unbalance the game in a variety of ways.'

He goes on to say that "Fallout 3" was always designed to be replayed several times as a variety of different character types, so if you're looking to expand your play time you may want to start from scratch. He did leave the door open for future level increases, though:

'We're very happy that people enjoy Fallout 3 so much that they want to keep playing it, and I'm sure we’ll look into addressing these concerns in future games.'