Going non-canon is fine, as long as you can convince the player that what you're doing makes sense and is something they can convince themselves to believe in.
The above map instantly shatters any suspension of disbelief I might have had, simply because if they can't take the time to create a proper and complete looking map, it places doubts on my mind that the actual campaign will be much better. (And the "we haven't explored it yet" arguement is bollocks. The map is from an all-knowing point of view, and even if it wasn't, you should have some cheap "Unknown regions" graphic or something to fill in all that empty space.)