So, let there be no more speculation. Sentry is staying dead for story reasons and NOT to make way for new Marvelman adventures. :) Here’s what was heard at NYCC 2010:
The Sentry came up again later when a reader asked how they could have approved of the character’s death when it seemed to run contradictory from everything fans had seen about the characters “return” from the beginning. “The reason this death-scene stays is that Robert Reynolds wanted out,” said [writer Brian Michael] Bendis. “One would argue that when he resurrected himself, he didn’t want to go. But now he wanted to go.”