I will be as specific as possible. I'm looking to essentially digitize existing building maps. Rooms, doors, and halls have numbers. Each room has a door, power, and data ports. Wall thickness is not important. Making sure the walls are to-scale - Wall A is 30 feet, wall B is 15 feet. Wall A should be 2x as long as wall B on the final product - and I shouldn't have to eyeball it, like in MS Paint or GIMP. The buildings are relatively large with over a hundred to several hundred rooms each, and each needs to have a visible room number. It will be printed on 11x17 paper so it can't be crippled to be unable to output at a decent resolution. Our current paper map has pixelated room numbers that are often impossible to read.
A plus would be the ability to add layers, such as the example I gave before - coloring rooms based on the IDF/ICC that it is directly connected to. Or each classroom would could have an additional label with the teachers' name.
The problem is that I've used some decent 3D CAD applications and am looking for the ability to add relationships - such as "This wall is attached here to this wall" - so that when changes are made to one object, other unlocked objects will adjust themselves. However, I am working in a strictly 2D environment. Perhaps I'm looking for too specific of a program?