Unless something's changed since I bought my big maglite, the outer ring only controls the beam pattern, and the button just gives you on and off. Things might have got fancier in the meanwhile, but mine still does what it needs to.

Modern ones work as you describe, but you can also press the button multiple times quickly when first turning it on to control the brightness. One press for bright, "double-click" for average, "triple-click" for dim.