I believe Spine Carapace is the same cost upped as non-upped, but either way, I have to disagree.
Both of these are extremely powerful shields, and they need a higher cost. The ability to play one of these in the first turn or two isn't really balanced. Take Hope, for example: you're talking about being able to have a shield out--possibly in the first turn, turn 2 at the latest--that cannot be removed by your opponent. Add that to the fact that RoL have 0 casting cost, and you can set up a Hope Deck before creature control is even really possible.