You need both, but if you are going to skimp out on one, it's much better to be stronger technically than artistically. Rachael and Shawn both prove this. Artistry is nice to see, and it will hold a skater/gymnast up when they are struggling, but if the technique is there and the artistry is a little lacking, you can still rake up enough points to be competitive.
Rachael/Shawn aren't really good comparisions. Shawn was really spectacular when it comes to tricks. She had G skills on every event (even her bars which other than that dismount was very weak for her) She had no code whring whatsover. She didn't have the greatest technique, but you can't deny that she was truly doing some very difficult skills.
In contrast, I don't think Rachael is all that special technically. Once in awhile she may do a 3flip/3toe but that's actually kind of rare from her. She has all the jumps but I wouldn't call them spectacular. Like Kim/Ando's/Mao's can be...She's just consistent.
Probably a good comparision between Shawn and a skater would be someone like Ando or Irina S
Yeah, the whole gymnastics business was pretty interesting, although I feel like artistry should be less important in gymnastics than in skating. In gymnastics, only the floor routine is set to music, so there's really not much room/need to be artistic in the other events.
The name of the sport is artistic gymnastics. Music isn't the only thing about artistry. Its also how skills are presented. Beam is something that should also be artistic. Bars can be made beautiful too and a well done vault should have good form amplitude, not just be chucked. See tapes of the old Soviet gymnasts.