First , an IDE does not to include a GUI contrary to Agide (which seems interesting anyway. thx for the ptr).
Second, it takes so long to learn an environment that you want it
to do a lot with it. A text editor that cannot act as an IDE is not of much
interest to me. Too bad, vim fall very short of that.
Also "real IDEs" have a way to force things on you (define file
for projects and so on) so sometimes it is interesting to have a best that is half-way between a full-fledged IDE and an text editor.
About the vim pager
Sometimes you get to display stuff that you can't scroll back to when you have gone thru. I don't have a interesting example out of hand. Anyway, say, you want to list all the options:
There is more than one pageful so you get a pager. But you can't scroll back or make a editable buffer out of what you got.
At least, the new vim user I am don't know how to do it.