Could you possibly post a couple of screen captures from your PC, one showing the original title art and the second showing a frame of your video of the same? That way we might see the problem and how severe it is. Computer screens are much more 'revealing' than TV sets when it comes to video. What looks obviously bad on a PC monitor may be invisible on a TV screen.
One thing that might cause this distortion is the type of video file compression your editors are using. Lossless compression is best, but may not be a viable choice due to the large file sizes. DV has some loss, and after a few editing sessions can take the edge off of graphics. MPEG-2 has a lot of loss and can't really work on more than one session without severe distortions creeping in.
Fav quote - "Experience is whatcha don't get 'till ya don't need it no more."
System - Athlon 1.4GHz, Win98, Hauppauge PVR250 receiver and compressor.
Software -Magix Movie Edit Pro 10, Nero 6 + NeroVision Express, Moho 4.61, PSP 8.1, Bryce, Quicktime 6.52 pro, Goldwave 5, DVD-Lab.
Cameras - Panasonic GS9, Canon ES8400V, Canon EOS D20 and Canon A70