Speaker size and soundstage

Question: for floor standing speakers, how does speaker size affect sound stage, bass response, and the depth of music?

I’m searching for a new speaker, and just tested Dynaudio Contour 30 against Tekton Electrons (16x18 room with cathedral ceiling). Tekton’s are bigger (48 vs 45 high, and 10 vs 8.5 wide, about the same depth) and had a much larger sound stage and greater dynamics and depth. Tekton’s as a rule are much bigger than most other brands, which can be imposing in a room, but the size must equate to a greater sound stage. 
But can a smaller tower be designed to achieve the same sound stage and bass depth of a bigger speaker? If so, what what speakers pull this off?