Power Creep
From LOTR-TCG Wiki
Power creep is an informal game term. Power creep is the tendency for new cards to be stronger than older cards. Which sets in particular were examples of power creep and why power creep happened in this game (and continues to happen in other games) are both controversial topics. There is however a general consensus that the power level of cards in general increased over time: compare The Balrog, Durin's Bane (2C51) , from the second set, to The Balrog, Demon of Might (19P18) from the last.