In deed. Take a look to Unreal Tournament and later UT's. Making a nice map on the original UT is prety easy (and very similar to DooM but in 3d). On 2003/2004 it' keep being not too hard and you have the static meshes to make your map more nice. But, UT3 map creation become a little nightmare.

Also, moderm DooM source ports, added a lot of features to DooM. For example, you should take a look to kdizd , Real guns mod for Zandronum (This mod, makes Modern warface and call of duty a piece of shit!), and a huge list of maps and mega wads that have a insane quanty of quality work to be funny & highly detailed. I keep playing DooM (using Zandronum) on multiplyer... The best game of all time.

I only hope that ID take a look how do a proper remake of a classic game, taking a look to Stainless work with the new Carmagedon. Really is better that Carmagedon 1 & 2

Modern Doom source ports like ZDoom and Zandronum even have a simplistic scripting language built in. It's called ACS, and was taken from Hexen.

http://zdoom.org/wiki/ACS

Granted, it's a very limited scripting language (up until recently it didn't even have support for dynamic strings), but I imagine it has served as a gateway to "real" programming languages for at least one mod-maker.

I've thought about this in relation to Minecraft as well. In environments like Second Life or modding scenes for higher-fidelity games, the barrier to entry for content creation is higher. It's much more difficult to make something that looks good in comparison to everything else. Adding constraints to that "everything else" actually helps to encourage creativity, by enabling more people to meet the standard.

Particularly, the two-dimensional map layout (no room-over-room) is much easier to make maps for.