For me I would really like a low profile triple knee shin guard. I have had a lot of trouble finding a pair that's slim enough to fit under my pants and can still offer a decent amount of protection. Toe protection isn't necessary if you have good plate shoes however ankle protection is nice. One thing that's really nice is about the GD shinguards is the strapping. The velcro straps are really nice. I think if there was one extra strap on top of the guard it would reduce the twisting and turning. My hockey shin guards have the same strap system and I can't go out on the ice without taping them for fear and annoyance of them moving out of place while I'm on the ice.
So, in conclusion, my dream shin guard would be a low profile, triple knee shin guard with well placed velcro straps.