Don’t use the motion tab or wireframe in the viewer to move text, as soon as you do it looks bad. Under the control tab there are controls to move your text, use them and your text should look fine. Make sure that under the motion tab the position of your text is at 0 & 0 for the center point. Don’t know if in FCP4.5 has the “motion filtering quality” but that was to change the way still images looked, and it made a slight change but it stills not as good as setting the sequence field dominance to none.