Would trench's be built for defensive positions? but not as a platform for assaults like WWI.
Trenchs in WW1 were pretty much defensive on both sides, hence stalemate. Treanchs in WW1 could be attributed to the machine gun, but modern trench warfare actually started towards the end of the American Civil War.
Technology is how trench warfare was overcome in WWI. Well that and the fact that all countries involved were preaty much completely ****ed. But things like the tank the plane paved the way for ending it. Korea was poorly trained (if at all) armies and full of jungle so again trenches were used rather a lot. I wonder what the world would be like if nukes realy were used there though. Hmmm. Ah who cares.
I would say that contemporary military tactics are trending away from the use of trenches, way far away. But, who's to say that the right set of technological advances (or major global calamities) would not usher a return of trench use in war?
For the near future, though, I would only expect them to be at least as limited as they have been in the recent past, that is to only have a significant role when the armies involved have what would be considered very limited resources, such as in the Siege of Sarajevo in the early 1990's.
but with modern gear like night version scope and thermal scopes system could we be able to do the ww1 style of trench warfare system ..
also think about airpower and it effects on modern warfare and how bombs and smart missles and other things would come into play dureing warfare ..