The company said: "As you may know, this game is the product of a unique partnership between longtime Metroid producer Yoshio Sakamoto, Team Ninja, and many other individuals and groups, all of whom have set very high standards for this latest installment in the series. Although it's taking slightly longer than expected to complete the project, we're confident that fans will find it to be well worth the wait."
The other delayed title, Sin & Punishment: Star Successor, was pushed back for a different reason.
"We're striving to provide the best possible pacing for our summer game launches," the statement said. "A June 27 launch allows gamers to enjoy Sin & Punishment: Star Successor without having to rush through Super Mario Galaxy 2."
Super Mario Galaxy 2 launches on May 23. Metroid: Other M is set to launch on August 31. Sin & Punishment: Star Successor will launch on June 27.
Maybe they don't want to cause a 'core Nintendo fan panic' when they start seeing titles delayed all the time. Though that was never a concern for them in the past.They only do it now because whiny ones became even more whiny.