Yeah, after taking the drastic approach of moving to the other side of the world to take on the challenge of playing a different sport with some similar skill sets and the aim of playing for England, he decided to go back to what he knows because he doesn't want to spend another 18 months learning how to be a 6...
He got what he wanted from Union, played for England, got a world cup experience in a bigger sport.
Completely understand Hooper not wanting him back in the changing room, there's at least 1 player there who deserved his spot in the rwc squad more than he did (and also came from RL), who had not just had a half decent game or 2 at centre but been consistently good there over a period of time and already played well for England. More importantly Burgess has shown a lack of willingness to fight for the shirt (Bath or England), which for guys who've been at Bath a long time can't be very nice to hear. He doesn't represent the promise of his arrival, either he completely underestimated what it would take playing prem rugby union, or he got exactly what he was after and is now done with it, either way it doesn't reflect too well on him regardless.
On the flip side, David Denton is a very good signing, already a good international flanker and we'll never know if Burgess would ever have been as good as Denton already is.