If you want to compare it to something, compare it to Titan.
As for those 'cost calculations' of cards... I guess according to that, Dimensional Shield should cost: 3 turns of no damage + 1 card = 20 ?
Dim Shield: 3 turns of no damage
for 6
+ Shield Slot + 1 card.
1 turn of damage prevention is different than the 1 turn of delay (to ready the ability) of Magnetic Blade before the effect takes place.
I was using a similar attack weapon with a similar cost with an ability that was not influenced by its attack value. Aka Lobotomizer not Titan. Remember this was the comparison to the usage that prevented the smart opponent from playing weapons.