Wow. Thank you so much. That's probably the biggest compliment I've ever received. I never thought I'd be asked about my general philosophy on bass playing. I've literally been sitting here for the last 15 minutes trying to think of what to say!
My general approach to bass playing is to give whoever wrote the song the confidence to spill their guts all over the stage. It takes tremendous courage to stand in front of a crowd and sing a song or play a solo and I want that person to feel as comfortable as they can. Think of that "Footprints In The Sand" poem/prayer. As corny as that sounds, that's my philosophy. It's not about me.
As far as shunning exercises for learning songs, it depends on the context. Learning music sometimes requires exercises (scales and patterns), but learning a technique doesn't. For example, I want to be better at using a pick. I'm not going to sit and do picking exercises or run scales up and down the neck, I'm going to play Darling Dear or Giant Steps or whatever song I want with a pick until I get it right. It's much more fun and interesting. When we learn how to speak, we don't learn how to "speak angrily" as a technique, we just speak angrily when the occasion arises.
Concerning my training, I have none at all. I'm completely self taught. All my knowledge comes from years and years of just wanting to know how music works. My wide range of musical tastes just comes from a passion for music. If I like a song, I MUST know what the chords are, must analyze the rhythm, must learn the bass line, must learn how the melody fits with the chords underneath. It's ridiculous.
Finally, my tips on how to get where I am in my musical development? Never stop being curious. To quote Mark Levine from his Jazz Theory book: "Good music is only 1% magic. The other 99% can be explained."