Anna Yolei wrote:
I remember reading that BOBW was a two-parter because Patrick Stewart had yet to sign on for season four, and TPTB wanted a way to write him out in case he walked away.
This has been said many times, but in one the blu-ray docs (think it was from season 1) Patrick Stewart recounts being shocked when he was told by his agent that he had committed for six season when he signed onto the show.
I think it more likely that Stewart may have been considering leaving the series. But, again, I don't recall ever reading any interview or blurb from Stewart or anyone (working on the show) that he was seriously considering trying to get out of his contract.