Great idea. the buff is excellent same with the blockade. (blockade has been added to the list along with your name)
My only worry with the blockade is that it can make the battle unfair to the defender, since once his supplies runs out he loses.
However, its a +1 since this can speed up battles on low level players who do not have good offences by starving high level players.
On a overall note, this would cause a better change to the game, allowing islands to change owners much faster, increasing the game speed.

