A border makes it so everything almost like stays in the sig, it makes it look nicer, there is a tut on pro sports gfx that you can use to
Another rather quick one just to add to the thread..
It lacks a border, text could improve a bit, the cut outs need to be a little better, try adding in a background and some effects on the players to blend them in.
I did this one in my sleep what do you guys think?