in most instructions they say that you make a V with your thumb and your index and midle fingers separate slightly and hold higher up toward the handle ...but it seems some people smash with no finger separation - its like they just make a Fist .... is that normal? ... to smash with just a fist, lol - seems like there is much loss of control :/
http://www.badmintoncentral.com/badminton-central/content/view/81/26/ Err, I don't think it's "normal" compared to what most people do. With a fist, you lose power from your forearm pronating which would meam a big lost of power. It's hard for me to even imagine trying to hit like that. Maybe they finish with their finger lowered?
This is a more complicated issue than it might at first appear. The basic advice is simple: never use a tight, fist-like grip. You do not need to change your basic "forehand" grip for a smash. Yet when you observe players smashing, especially with photographs, you can see that the grip is tight and there are no gaps between the fingers. This often causes confusion. What is actually happening is that you are looking at the grip at or after impact, when the fingers have tightened. Make sure that your grip is relaxed; it will naturally tighten as you hit the shuttle.