You can parse text instantly too, just probably has a limit of up to a few words that you can perceive "at once" as you say. Editing a whole 3 pages at once is the same as saying in photoshop you can edit a whole magazine worth of images at once, you also can't.
As with anything the shorter the feedback loop the better. The difference being that an image has an information density which is much higher than text, "image worth 1000 words", and you can make sense of it easier.
If you want to edit lots of text and see if it flows well quickly, some other ways would involve mapping the textual representation to something we can perceive quicker. The same way sometimes systems will have different sound tones for different actions, making a skilled operator able to detect mistakes by "listening" to the UI. If you can represent textual changes in an aggregated visual form, you might get what you describe.
For example if you could make nice grammar produce a nice musical sound when "read" by a computer program, you could potentially assess for correct grammar quicker by listening to the whole thing in much less time than you'd take reading it.
As with anything the shorter the feedback loop the better. The difference being that an image has an information density which is much higher than text, "image worth 1000 words", and you can make sense of it easier.
If you want to edit lots of text and see if it flows well quickly, some other ways would involve mapping the textual representation to something we can perceive quicker. The same way sometimes systems will have different sound tones for different actions, making a skilled operator able to detect mistakes by "listening" to the UI. If you can represent textual changes in an aggregated visual form, you might get what you describe.
For example if you could make nice grammar produce a nice musical sound when "read" by a computer program, you could potentially assess for correct grammar quicker by listening to the whole thing in much less time than you'd take reading it.