Great discussion guys.
We went through a process of general streamlining - removing everything that was not essential or had little impact on game play, in order to make the rules more concise, and the game easier to grasp.
Removing the ability to roll fewer dice was one of those things. As a designer note - Along with this we removed other things like archer suppression (attacking a creature with a melee attack prevents that creature from making a ranged attack that same round), LoF (Line of Fire - a wall could block LoS but not necessarily LoF, or visa versa, which made for some interesting tactics), and others. I'd like to state for the record that I fought kicking and screaming to keep these things in the game! (I am expecting hate emails from the playtesters later tonight!)
I must concede that it is certainly quite realistic and feasible to roll fewer attack dice, but currently it is not in the rules. For whatever it is worth, Sleep was priced with this in mind (that only a small creature or attack can effectively be used to wake creatures up). Sleep would be a tad cheaper mana-wise if you could voluntarily roll fewer dice.
I love the fact that devs respond on this forum.
I find it hard to argue against streamlining the game, or doing anything to make the game more newb-friendly. LoF and Archer suppression sound really cool, but I can see how it could increase the learning curb pretty significantly, and frustrate a new player when their opponent uses it to ignore their wall.
One of the things that is apparent in the design process of this game is the desire to make everything as intuitive as possible. Choosing to roll fewer dice seems pretty intuitive to me, but then again I haven't playtested the game for hours on end, and have only seen hardcore gamers play the game for the first time. Ultimately, I imagine it is difficult to determine exactly what mechanics players will grasp quickly and which they wont, so I suppose there is no wrong answer to the question of what mechanics to remove to make a game accessible. It sounds like I would fall on Arcanus' side, but Dreallin's answer reveals a flaw in our arguments, because a larger portion of text would have to be inserted in the rulebook explain how lowering attack dice works when effects modify the amount of attack dice normally rolled. Even if the barest of explanation was put in, which implicitly deals with Drealin's point, I imagine there would still be some confusion.