I agree with tundramagi on most things. UnrealED 2.0 was much buggier then NetRadiant is now. I got tons of crashes when I used to map in UT99 which was driving me nuts (even got crashes in UT2004's editor though less then UT99's). With the Radiant series I hardly got like 4 crashes in many months of mapping which to me seemed incredible. I also consider Radiant one of the best map editors out there... it's very well arranged and easy to use.
And true, I think the fact the UT series always had UnrealED with them made them as they are today. For instance there are tons of UT maps all over the net for all UT series, while for Nexuiz there's only a small bunch on maps.nexuizninjaz.com which I think is sad we don't have more. If Radiant would be placed right into the game for everyone I think we could soon reach a greater performance on maps as well, and this would also help with raising the popularity of the game and having more high quality maps.
Setting a link for an external download location... I don't see the point to that myself. Some like mapping on laptops where they don't always have internet, and this would kinda create a "download this download that" dependency. I always thought it's best to have things as open and easy as possible, and imho just including it would make things much easier. My personal belief is that the NetRadiant folder would be best placed directly in the main Nexuiz folder next to nexuiz.exe, or if not maybe in a Tools folder where later on we could also include other small tools over the years
Also it could be mentioned in the package that NetRadiant is a separate product so bug reports should not be filed to Nexuiz about it (possibly include a link in netRadiant to its own bug reporting area so people easily know the difference). Hope this will be possible sometime in the future at least.