Why do you think he's a lame player ? Because he doesn't play complicated bass lines ?
He plays exactly what the song needs, and his playing is a huge part of making U2 sound the way they do. With all the effects that Edge uses, Adam and Larry's job is to hold down the bottom end and glue it all together... and it works.
I'm not a huge U2 fan or anything, but to say someone is "lame" because he plays "exactly what is needed" is immature and honestly, pretty ignorant.
If the song NEEDS 3 notes, you shouldn't play 4. Music isn't about showing off - it's about "expression". Just like all paintings don't need to be "complex" to connect with people, all musicians don't need to play "complex parts" to connect.
I'm calling a hold on this one. It's like a chicken and egg thing: it's "exactly what is needed" because that is the sound created and associated with U2. Clayton was not hired because he could play bass. They were all pals who decided to form a band and he became the bass player.
It could easily have been another person, a different player, maybe someone who played more notes but still sounded cool within the overall band vibe.
Let's say they still made it huge (and who's to say they would not have, we're just speculating). Then it would be said that bassist plays 'exactly what's needed'.
Clayton plays simple lines because he had to start that way as a newbie. The band took off and the sound remained....
My .02....