When listening to music I often try to pin point these things.
Sometimes I never can tell where the bass guitar is. I'd like to understand more about how the bass guitar is used. Some bands I really can't hear where the bass is, and all i can single out are the guitar tracks not the bass. In some bands it seems the bass guitar is more to add depth to the sound and just make things more full, like they're just kinda imitation the guitar player or whoever's playing rhythm. Tool is a band where the bass sounds like a main component in their music, not just playing rhythm all the time, and is more out front. Justin Chancellor is a great player. He's the most underrated bass player. In other bands i can rarely point out the bass guitar. I don't listen to Motley Crue too much, but i remember when i found out that Nikki Sixx was their bass player. I was surprised because he is very well known, way more then Mick Mars is. I should listen to some Crue and pay attention to Nikki Sixx and see how noticeable he is on their records. He is their main songwriter, so i'd expect him to be very loud in the mix.
And does Maiden really need 3 guitarists? Have they ever addressed the reason why they chose to keep all 3 in the band?