Pengu, it's not as much the capability of the machine...what the DP 2.7 can or can't do, but the letdown that's occurred from Apple not meeting their goals. This revision needed the 3GHz mark for marketing purposes more than anything else. The only acceptable deviation to that, IMO, would have been releasing a slightly slower (slower as in lower frequency) dual-core processor model.
They unveiled the original G5 in June of 2003 at a max of 2GHz with the promise of 3GHz within a year. The year has come and gone, and another pretty much has, with no 3GHz in sight as of yet. The first year saw half the goal (1000MHz gap, 500MHz upgrade)...now it looks like the second year (500MHz gap, about a 250MHZ upgrade) will follow that trend.
Don't get me wrong, I think they really need to address the ancillary things too...stuff like the amount of memory they ship with systems. Granted 512MB is better than 256MB, but 1GB should really be the minimum; especially on the high-end model. Bringing the 'stock upgrade' price on the RAM under control is another much needed change. Embracing PCIe for the video instead of AGP 8x would also be wise.