Well ive mapped for years now on goldsrc and source. The one thing i hate or always hated was a leak.
There anoyying. Extremely hard to find (especially in goldsrc) and make compiling either very very long and ###### or really fast and nothing good.
I dunno how or what leaks will do in ns2. But heres my suggestion for the compile process.
If you can some how make it so when it notices there is a leak it will create 16x16 bright neon orange boxes where it is till the leak is filled. So when you run your map you can very quickly find that leak and fix it.
Now im just saying this i dunno how leaks or skyboxes or compiling will work for ns2 until it comes out. But heres just an idea if you have nothing yet.