I wouldn't mind adding such a thing (innate self-procrastination?) but there's no more room on the upped card. This sounds silly, but is kind of an indicator that it would start making the card complicated. Assuming the upped one isn't complicated yet.
If such a slow-down is required, i will just do it by lowering the damage to 2 (bare minimum imo) or adding a fire cost to the unupped one. Do you think it is? Because having a permanent that can directly harm & kill yourself is one hell of a drawback already...
EDIT: ARTHANASIOS posted while i was writing. So:
Bond of Amplification is meant exactly for that, ending the game over few turns, provided you have taken a good enough early HP advantage. I agree that Dim shield and the likes don't need more counters, but now there is SoW on top of Momentum, Shard of Freedom, and every PC in existence.
Dim shields are no longer the very strong stalling card that i knew when i started playing, now we need a wider array of shields, and Reflective shields have been given much more use since SoW came out. This is another card that would make them possibly as useful as other shields i guess? Becaus let's face it, they absolutely wreck this card. In any case (except perfectly equal HP) the owner will be the one damaged every turn. Countering massive damage with a 1
cost immaterial shield sounds fair to me, on top of all the other counters (see in original post). Same deal as Purify VS any amount of poison.
Also it makes
abit more useful: Luciferin, Holy Flash, Miracle, Reflective Shield... i'd be happy about that as a bonus. I agree that the damage output would normally warrant a higher cost (14
for a Phase Dragon, sounded like a good basis at first), but then again i remembered that balance implies that anything that can backfire at all gets a compensation somewhere, usually in cost. That's why upped Panda costs more than unupped, it cannot hit your creatures.