i think a card like this needs a drawback, it just seems like to much damage instantly maybe the creature could get delayed for a like a charge up period 2 turns and give your opponent a chance to kill it before it kills them
another thing im wondering is how would this work with sundials and SoP, it says creature dies on hit but gets + 5/0 so could you play multiple final charge and giving him +5/0? even though the attack doubling dosnt stack like overdrive
but other then that sounds like a really fun card to use 
I'm gonna modify this card soon, so it would do spell damage upon attack, and I'll add more drawbacks: that you can't play any more cards this turn, and the Charged creature is immaterial. The
sign is used, like SoW, but it still dies upon attacking. Do these modifications make it too much of an 'Aether' style?
Anyways, SoP would only give +1/+1 to Charged creatures, in a flooded area or not,
or not, if and only
if SoP affects immaterial.
Sundial prevents it from attacking, sparing your opponent for one turn.
The
card can't be stacked, which means you can't play it on an already Charged creature, thus you can't keep adding +5/+0's.
