I don't think "simple" is an accurate way to describe Coda. For one, its complexity is at least on par with Icon (I'm not counting Spacedock here, which is a standalone document).
Coda is more streamlined than Icon, which I often found clunky. I personally prefer the smoother random curve of 2d6 vs. 1d6 that allows players to better gague what their skills allow them to do.
Coda also does in one book what Icon took three separate books to do. I also honestly feel the Narrators guide is one of the best toolkits in the gaming industry.
And, while I'm a gearhead at heart (I treasure Traveller 4th Ed's Fire, Fusion and Steel supplement), Coda's starship combat rules are beautifully cinematic, allowing the GM more freedom to describe the scene with words, rather than numbers. Star Trek's space combat has always been about the cinematic feel, even when everyone's spouting technobabble.
Icon was good; I like Icon (and still keep a couple sourcebooks around for flavor), but Coda is better at keeping the Star Trek "feel," IMO.
As with everyone, of course, it always comes down to personal preference and taste.
Davy Jones
"Frightened? My dear, you are looking at a man who has laughed in the face of death, sneered at doom, and chuckled at catastrophe! I was petrified."
-- The Wizard of Oz