The Cast Show Off: Alan Doyle, the actor who played one of Robin's cohorts (Allan A'Dayle), is the lead singer of the Canadian band Great Big Sea. He sings throughout the movie, usually while playing a stringed instrument.
The Danza: A close enough reverse one where Allan A'Dayle is played by Canadian singer Alan Doyle. Another reverse one is William Hurt playing William Marshal.
Executive Meddling: Probably to shorten running time, a key scene was cut from the theatrical cut where Robin comes out as an impostor of Sir Robert Loxley at the first opportunity. In the present version we are led to believe that Robin successfully maintained his deception until the battle scene where suddenly everyone is cheering him by his real name Longstride. This creates a plot hole because John outlaws him partly for impersonating a knight. Nearly 20 minutes of footage were cut, but were restored in the home video release.
Fake Brit: Robin and Marion are Australian, King John is Guatemalan, and Sir Walter is Swedish. The Merry Men include two Canadians and an American.
Stillborn Franchise: A planned sequel was canceled due to the film's poor performance at the box office.
Typecasting: Father Tancred, the greedy priest who Friar Tuck replaces, is also the jerkass Archdeacon in Rev and smarmy Fra Pavel in The Golden Compass. Corrupt and self-serving men of the cloth seem to be a speciality.
Troubled Production: As noted in this interview, the script got hit with extensive re-writes, turning it from a Sympathetic P.O.V. story of the Sheriff of Nottingham, to a Fight Club-esque story, to an origins story of the title character. Also, Crowe and Scott weren't getting along well on set, which eventually soured their relationship. In addition to that, the film's budget had ballooned from 155 million to around 200 million according to some sources and around 16 minutes were cut before its theatrical release (which were latter reinserted into the home video release).
As detailed in an interview with one of the original writers, the original script (PDF file), titled Nottingham, was about a heroic Sheriff of Nottingham who is caught up between a power struggle between John and Richard - while at the same time investigating serial killings in the area. Robin Hood, portrayed as a self-serving rogue, is a Red Herring suspect of the murders, but in the end he and the Sheriff work together to resolve the conflicts. The script was bought by Universal, and Russell Crowe and Ridley Scott got on board. The script was rewritten to make Robin Hood an alter ego of the Sheriff, and then the original story was replaced entirely. The only thing the original script and the final product have in common (besides the general subject matter) is making the Queen Mother Eleanor of Aquitaine a key supporting character. What makes this bad is the realization that the screenwriters of Nottingham have no rights over their unused script, essentially leaving another original and unique take on Robin Hood unable to be used, and the writers with no involvement on the finished, Brian Helgeland-written product save co-writing credits. That's cold.
Originally, Crowe was set to play both Robin Hood and Sheriff of Nottingham. The idea was dropped.