I've had the chance to work on CAD systems for the design of complex electronics for many years now, both in commercial tool and in-house tool settings. Here are some things I would like to see (and help create) in a CAD framework:

• Explicitly supports (and requires) documentation of the designs created with it;
• Is itself (the CAD system source code) extensively documented;
• Has solid cross platform engineering designed in from the start;
• Is designed around component software technologies:
  • thus being open and extensible, in both programming and human interface;
• Has Internet integration (http, ftp, e-mail):
  • to allow group collaboration over the Internet or intranets;
• Is engineered such that "software agents" can observe the design taking place, and perform tasks:
  • for example, support teaching of good design techniques and new design techniques; and
  • for example, support of "CAD Flow Safety Checks", to ensure necessary analysis get performed;