I have a K4, and I find it really hard to access the drill pin guide (the thumbscrew that locks the jig's proper height setting) when the vacuum attachment is in place. It seems that adding a phillips or square drive to the end of the drill pin guide would make it easier to turn.
I just pull the vac housing away, but if a groove was filed in the thumb screw, then a screw driver could be used.
Kreg would have to add a philips or square drive at the factory.
I just took about half a dozen strokes with a hacksaw to it. Put a nice screwdriver slot in there. Thing is brass so it isn't a real big deal. I do agree that it wasn't overly thought out though.
Since we are "improving" Kreg's designs, I find it difficult to place the drill guide into the base, since it appears to be a slight interference fit. Once it's started, it slides easily, but by just touching both sides of the base to my grinder, I added a chamfer on both sides and facilitated insertion of the drill guide.
The next modification involves holding the vacuum hose ...