Yea the walls could be bogus but I haven't seen anything like that for a long time.
Well obviously that's because mtgoxlive changed the scale to be the same for BTC/USD sides of the graph. Before, even when BID side was 3 times higher than the ASK side, they displayed the same height. Now it's adjusted to reflect the actual ratio and you don't have to calculate yourself.
Yes, now it is much better than before (bid side was plotted in BTC and ask side was plotted USD). Now the asks are also plotted in BTC (the ask axis labels are still in USD).
My preferred option would be to see both sides plotted and labeled in USD (with the BTC amounts in the mouseovers). Then one can see how much USD can be cashed in/out to reach a price point, at a glance and without using mouseovers.