Box Office Bomb: Subverted. It is often cited as one of the most notorious box office failures in movie history, but that's not doing the research properly: it did flop in the US, but then it went to the foreign market and performed very well there, easily making back its budget in gross revenue.
Executive Meddling: Unusually it was actually Costner editing with rumours of him firing Reynolds.
Relatedly, script doctor Joss Whedon says his job was basically taking notes from Costner.
Trailer voiceover legend Hal Douglas narrates the opening.
Novelization: Written by mystery/comics writer Max Allan Collins, the novelization did a good job of expanding character backstory and tying loose plot threads together.
Troubled Production: The ballooning of the budget ($100 million to $175 million) is the lesser part of it. The Executive Meddling made it even worse. The hurricane trashing the main set didn't help either.
The version that Universal ended up buying was basically a kiddie flick — Enola was the main character alongside two of Helen's own kids, the Mariner was a human and largely a supporting character, while the early version of the Deacon can only be described as being how you'd expect the Adam West Batman series to characterize him. Needless to say, the subsequent drafts took the film in a very different direction.