I find the CK to be frustrating but fun actually. I have used editors for many games such as Quake2(Quark is the name of the one i used i think),Quake3,Quake4,DooM3, Unreal2,Far Cry, Crysis, Halo... The CK is harder to use than the Crysis one but the hardest easily has to be the Halo editor. As its not 1 editor... you have to use several different programs to make lvls for that game.. if i remember right one of them is called gorilla... could be wrong tho lol.

ID's editor has up till DooM3's engine used a prosess that is kinda like 'baking' your lvl. It has to generate light maps and if you dont it will look like what skyrim looks like in the CK with lights off(everything is overbright). So if you are making a Quake3 lvl and want to test it you have to wait several min for it to 'bake' the light maps. Something that Unreal,CK,Doom3,Crysis dose ingame. If you want to make a spot light in Quake3 you have to make 2 'info null' if i remember right. Then link them, then set the property's of the light to point at the other info null. Then set color, brightness, fade, cone radius, distance to the linked null effected how far the cone lit. Like linking to other nulls(switches, traps, monsters) or setting it to blink or fade or fliker. Then you have to generate the light map. THEN you can go into game and see if its big enough or bright enough... I think it has an option to only generate only lightmaps of lights you have changed... but its been years. Making AI pathing maps took time aswell. As buggy as it is, throwing down Navmesh is is at least more fun than clicking a button and waiting for it to work for you. If it works at all.(if you have a hole in your lvl where you can see the void the ai pathing would freak out. Like the void was outer space or something. It would show you the leaks tho by putting info nulls in the lvl with lines pointing to the 'leak' ) In that game you didnt just use lego pieces and place them. You had to make boxes. The back side of the boxes had to be 'painted'with a no draw texture other wise the render-er would render the textures on the back side of walls. Probably why the CK pieces are transparent from the back. My point is it can and has been alot worse to edit games.

I would like to be able to hide lights separately form other actors tho. Trying to move a light if a dust beam is close by you WILL select the beam... I know you can hide it but it would be so much simpler to have the option to have lights separate as is the case in other editors. Thats kinda minor though over all its good imo.

Bethesdas editors have been the easiest editors ive ever used. They are straight forward and no middle crap you need to do just to play your creation. I can go in, plop something down, save and go in game to see how it looks.

I tried making a UT3 level, and i never figured out how to play it in game, and moving objects around was a pain. That being said though, the ability to remap textures in the editor itself was a nice touch.

If you select an object and press 1, it will make it transparent and unselectable. If you press it again, it will completely hide it. It has no effect on the end result in game. Very useful tip you learn in Bethesda's video tutorials.

I know about hiding things by pressing 1. But have you ever looked at a bethesda cell? soooo much stuff. Looking at a actor you dont recognize and trying to click on it to see what it is you will pick something else in the room. Just an anoience imo. Clicking and pressing 1 about 20 time... heh.

Modding Doom3 I took lvls from other peoples mods and linked them ingame. Moddifying the door switches at the end of the lvls to point at modded lvls. Making it so when you play though, modded lvls fit in to the game.

Modding Far Cry or Crysis the first thing i did was delete those attack choppers that kill you if you leave the path. Developers talking all kinda stuff about 'open world gameplay' should play skyrim/oblivion imo. In crysis or farcry if you try to walk around a camp to attack it from the other side choppers come and kill you... yeah .. "open" .. right. I understand the point of the choppers though. If players get in a boat and just go to the other side of the island they will find nothing there but bear ground as in each lvl 90% of the island is unfinished. Saving on memory i would think. but imo they put the choppers way to close to the play area. Kinda like if you try to walk to the imperial city or morrowind. you can with a little cheating but you dont find much when you get there. i wouldnt expect them to put time into making play area you wouldnt even see. But skyrim at least dont punish you with attack choppers!

As for UT3 if its like UT2/2K/2k4 you can mod a peramiter so it shows up in the multiplayer list. I dont know how you would add a lvl to a single player UT game though. Quake3 and Doom3 its the same thing exept i found out how to link them in single player.

edit : now i remember, IDs games have a txt or config file you just add the multi player maps to that for them to show up.