Since it's not gonna change the map, I can tell you this: With World Editor Unlimited WEU, you can open the map, export the triggers and the object data. Then on a new map you can import 1stly the object data, then the triggers. The idea is that if you import the triggers only, those triggers that don't find the units they are using will have 0 value and you won't know how this trigger was. But that's for triggers that don't use units on the map, in that case the trigger won't work and the value will be blank. Even if the actions using Variables become red (not working), you can create the variables so you will be able to restore big parts of it.
The other thing that can do it is:
http://infoceptor.net/files/war3/mpqviewer.zip
You can open the map and extract triggers and other stuff, it's the MPQ of a map. But what you will be able to see im not sure, that's why you have to restore the triggers in a new map.