There's a difference between a bass solo and a bass solo piece. You really don't have to be amazing at bass to pull off a great sounding song. Anyone can really do a impressive sounding bass solo, especially for a live audience. Most never see anything beyond the normal slower rhythm/ in the background playing, so anything out in the open/louder/faster will be to them this whole "oh my god you're an amazing bass player!" deal. What really is skill and great bass playing at any level, is the ability to make just a great sounding piece. Take Stanley Clarke's "Silly Putty" (or primus' cover of it, they sound the same), the bass is a large part of the song, but he's able to maintain a great sense of rhythm and melody throughout the piece, while still playing in a lead style. The drums lay the basic foundation for timing and rhythm, the bass adds onto it, makes that second layer and melody, then the other instruments layer over those two to create the song. It doesn't have to be a "yawnfest", the tradition "bump....bump...bump bump bump......bump" sort of deal, play your instruments!
If you can't check out Silly Putty, this is a great example of slower, but melodic and "great sounding" playing.
http://www.barefoot69.com/Solo%20Bass/Video.htm
Even John Myung, I'm not going to doubt his skill or ability, I've only really heard so much of Dream Theater to judge, but I don't see anything really special with his solos. Sure he can play fast and accurately, but I don't know, a monkey can do that. There's no emotion, no melody, no creativity.