I don't think Apple would ever consider their iMac range and it's design as "experiments", they've too much riding on this (as a mainstream consumer PC) for it to be something they're just dabbling in for the fun of it. It was the original iMac that bought Apple back to the forefront of PC design and computing and increased their market share by a rather large amount - and obviously something they'd like to continue. The original iMac took a number of risks in design and functionality, but it worked, unlike some other Apple designs.
The iMac to me is just a fashion item - like the original swathe of colours with the first iMac, the new model looks good, is better than the last one, and a good replacement for that old lampshare or graphite iMac. Just like the iPod will probably be the biggest thing this Christmas, people get bored of it's design, Apple release new ones, just like the new iMac design
The benchmarks for the iMac G5 ... just Xbench scores? It's not a very good benchmark program at all :P