Sneaking should be hard. Perhaps the amount of listen builds people are talking about is simply a result of tons of people relying on stealth in PVP. After all, it is one of the easiest ways to 'win' - stealth stealth, wait till enemy is unbuffed or whatever, gank, giggle and run away with the body.
A stealther's job should also be to know who to be careful around. Amplify is round-per-level. If the sneaker notices the person casting Amplify and doesn't gtfo, the sneaker deserves to get caught and killed. The best stealthers don't rely only on numbers.
I think we're assuming that everyone is going to be wearing two +3 listen rings and a helm of the bat at all times. I'm sorry, but there are way better rings to use than +3 listen crap. It's unrealistic to assume Amplify is a constantly-running spell.
Our current situation is balanced, and actually favors stealthy characters, if you pull out and look at the grand scheme instead of number-crunching. Yeah, you'll get caught by a fully buffed Bard/Ranger Hybrid who never changes out of his listen gear. But you can probably kill the bard/ranger hybrid because he's wearing listen gear.
Further - Aldarris, you mention that it's a 66 vs a 79 in sneak v listen. However, if you remove Amplify, we're talking 66 (assuming the sneak isn't wearing optimal sneak gear, otherwise it'd be 69) vs a 59.
Assuming Amplify is reduced to a +10, it means that when the bard is fully buffed against the sneak, for round-per-level, they have a 50% chance of catching the sneak. And that's with everything dumped into listen. That doesn't make sense to me from a balancing perspective.