This has come up before. It'll probably come up again.
If you duplicate (or create) a task in project mode, you can immediately see where it went and put it where you want it. Not so in context mode. Maybe you always want your duplicate task tucked in right behind the original, but I can't think of the last time where that was what I wanted to do with a duplicate. If you're in a restrictive view (next or available actions only in a sequential project, for example) the newly created action might not even appear (it doesn't in project mode). If you are going to modify the duplicate (changing the context, for example), it may get whisked off elsewhere in the display unless you are using a combination of view settings that makes context mode look similar to project mode. Given all of that, and the ease of right-click Focus in New Window where you can see what you are doing and don't have to disturb the current view, color me unconvinced that there's a far better way to do this. One might take the absence of the ability to paste into a context view in OmniFocus for iPad as an indication that they aren't actively moving to change this, either.
Sounds like you might want something like Curt Clifton's
Complete and Await Reply script if you are doing this frequently.