As mentioned in an earlier post, we've put together a list of things that we would like to see in the next 'true' Mac Pro. We won't call this list complete, but it is a pretty good start to making a machine that the name 'Mac Pro' is worthy of.
What should be obvious from this wish-list is that it pretty much describes updated versions of the PowerMac / Mac Pro models we loved so much. Apple had good products with those lines and form factors. If you're going to make a 'Pro' machine, it needs to have the items that professionals need all in one package.
What Apple did with the Mac Amateur is make a computer that had some of the core features of a professional computer, but made everything else an add-on. Want additional disks? Add on an external chassis with disk. Want PCI cards? Add on an external cage (that won't exist for months and will be crazy expensive). On and on. What we want is a fast / powerful computer that has the potential to house most everything needed. Clean, with minimal cables; because everything is internal. We want the Mac Pro prior to 2013.