The basic attacks are not meant to very high and mighty, no offense, I thought of them only taking 1 sec to charge at defualt, with an upgrade the will charge in half a sec. I just thought to make the basic attacks a little underwhelming so the default sword/bow aren't obsolete. The reason I think this should be a mid to late game weapon is because is only really shines when fully charged. And no, I don't think I mentioned an energy reduction, I mentioned upgrades to reduce the charge up times, so lets say before you have to wait 4 seconds to use 4 bars of energy in a tier 4 attack, now it takes 2 seconds for the same attack. But maybe the movement penalty is a bet too much, 50% at default is probably extremely frustrating to deal with, so it may be tonned down a bit. I am just trying to think of some drawbacks to keep this weapon from being op, even though it's mid to late game.
How about this, a basic sword swing will, as mentioned around the same size and the default sword, not including the staff and is unblock-able. At tier 2, the sword is twice the size of the default sword at the cost of 2 bars of energy, tier 3, it is 3x the size at the cost of 3 bars of energy, and at tier 4 it is 4x the size at the cost of 4 bars of energy, there may some special abilities the are unlocked in higher tiers, but the basic idea is to deal massive damage with only one attack.