We now have four nights of DC superhero shows on in a row; each with a similar visual aesthetic and editing style, sense of humor and pacing, and even character structure. The story beats even feel familiar, one day to the next.
I don't think they do have that similar an aesthetic.
Supergirl is far brighter and crisper and more colorful,
Arrow is dark and nocturnal and gritty, and
The Flash and
Legends of Tomorrow are somewhere in between. Even though TF is the "brightest" of the CW shows, it still seems to have a different visual texture to my eyes than
Supergirl does -- I'd say they were using a different film stock if it weren't all digital these days.
What's interesting to me is that Berlanti is also behind NBC's
Blindspot, which couldn't be more different from
Supergirl -- it's a much more glum, solemn, ultraviolent show about federal agents fighting terrorist plots, with massive, extended gun battles literally every week.
Arrow is the only DC show in the Berlanti stable that even comes close to it in style.