So, you think it would be less powerful than other cards currently in the game, that have survived the test of time?
I think we should draw a distinction between "more powerful than the average card"
and
"overpowered"
I hail from games where the terminology was different as such I use this spectrum:
game breaking, broken, under powered, balanced, over powered, broken, game breaking
A 1
spell for 5 damage unupped to any target would be over powered in my opinion.
A 1
spell for 15 damage unupped to any target would be broken in my opinion.
A 1
spell for 45 damage unupped to any target would be game breaking in my opinion.
Card designers should aim for the narrow window of balanced.