The wiimote will never be as effective a controller as the light gun. The engineering behind it prohibits its usefulness as a gun.
With that said, the engineering behind the light gun keep it from being useful with modern games.
Nintendo learned their lessons about controller attachments with the N64 and will be keeping them to an absolute minimum from now on. Instead they’re focus will be on using the expansion ports on the console itself, something Nintendo has very rarely done in America.