Here are some things that pop to my mind when thinking about this houserule:
Most importantly, the game is balanced using point values that take the spd into account, changing a core rule to weaken a stat skews the balance.
- Drastically punishes things that are >spd 6 by capping their charge range to spd+6 while everything spd 6 or lower has the same or higher charge cap.
- Ranged attacks are indirectly made stronger as they are more reliant and melee is slower.
- Surge becomes far more reliable and better than charging.
Single dice are way too random.
- If one absolutely needs to succeed, you basically charge at spd+1. The chance of going > spd + 3 is a coin toss. (Does the person suggesting this have a ranged focused army? :P)
- You replace thinking and planning with chance
It slows down the game with extra rolls.
- If that isn’t enough of a reason, the rolls are not fun let’s see how good my guy is, but let’s see if my guys can even run in straight line to attack without tripping over their own bootlaces. But only when they are attacking!
Personally seems like a terrible idea to me. But that might just be my tastes