In the original, the words seem uncomfortably crowded. More margin would help them, as has been mentioned. Stacking could help as well.
Honestly, though, if the original design was done by a plastic surgeon, he or she didn't do too bad.
Light-face letters seem to be popular among many people these days. Light-face strokes on sign work, however, can be weak.
Bobby mentioned "overglow." This is also called "halation." Light tends to spill beyond the edges of letters on a lighted face, encroaching on the inter-letter spacing. This often calls for wider letter spacing to preserve legibility.
Also, a light colored letter looks thicker on a dark background anyway, so wider spacing can be beneficial for this reason, too.
This optical illusion, that a light letter appears bigger, is also why the dark background has an advantage over the light background on this sign—it helps the skinny letters a little.
In my examples below, all the lettering is beefed up. And I've added more margin.
Having spent years back-spraying lighted signs like this, the third one would easily require twice the hours in the spray booth due to the need for multiple masking. Of course, a digital print eliminates that problem. It just doesn't last as long as paint.
Also, when I draw renderings like this, I usually show the retainer on the drawing, though I didn't in my sketches here. I am assuming the original design above is depicting the "visual opening" only. A typical retainer will cover an inch and a half of the face's edge and, of course, must be accounted for in the design.
Brad