What little thing bugs me is when the nameplate is a single color (or 2 color on three color numbers), but the numbers are one or two outlines. Why doesn't the nameplate match? Ex TB Bucs. It's not for spacing as the Jags older unis had them. Another little thing that bothers me is when you have a wordmark with multiple colors and a single color number. The final little thing is when you have a team with nice uniform colors and use the trim (Miami Canes football) and the other sports use a single color, but the tertiary colors on stripes (Hurricane basketball/baseball).
Nameplate lettering is considerably smaller than the numbers on the fronts/backs, and sometimes the sleeves. Therefore, to retain legibility, the lettering needs to be as clear as possible. Multiple outlines makes the lettering hard to read from a distance, and even on TV. If you can't read the name, what's the point of having it? The Cincinnati Reds and Texas Rangers are big examples of this.
When I make a concept (a rarity lately) my rule of thumb is this: one-color lettering always looks good. If the numbers are single-outlined, the letters may be as well. If the numbers are double-outlined or shadowed, the letters will be single color.
I give Nike credit for this lately...with the crop of unique fonts trotted out for a lot of the collegiate teams, the lettering has stayed very basic.
And for outlining, the more plain the style of numbers (varsity block usually), the better it looks with outlines and shadows.