I don't really divide between "raod bike" and "commuter." I divide between "road bike" and "hybrid."
My "commuter is a Dawes Sheila with full lights and a rack and two bottle cages. I can carry a ton of gear depending on which panniers I bring. I can attach a handlebar bag if like. I have a large seat bag so I can carry a bunch of tools and spares and patches and a pump. I also have a stem bag for food and anything I want handy while I ride.
It is a lot lighter than any hybrid, plenty tough for any terrain, could take pretty wide tires (28 maybe) if I wanted but I don't find the need.
it has a study but not harsh aluminum fame and a carbon fork with an Al steerer, so I can run a lot of spacers so i don't have to reach past my knees for the handlebars. Still, if it is really windy i can get in the drops and get a little bit under it.
When I think "commuter" I generally think drop-bars ... I guess a lot of peple think flat bars. Either wiorks .... the only difference is the seat and bars. The rest---frame, gearing, wheels, carrying capacity---should all be the same.
I do Not recommend getting what is essentially a weak mountain bike for commuting. A lot of people get bikes with cheap, heavy suspension forks and overweight frames and wheels which are way overkill for commuting but not strong enough for actual mountain-biking.
When I think "hybrid" that's what I think of--a fork which can't really take a hit, a frame too heavy for the street and too weak for the trails, and a bike which does neither roads nor trails particularly well.
Just my personal bias. Lots of people have hybrids and love them, and I am sure many do roads and trails well.
I would recommend any road bike with an aluminum frame and carbon fork, or all steel, or steel with a CF fork, with fender and rack mounts. Flat or drop bars is just a personal preference.