M14 Rules Changes

I know we talked about this briefly last month when it was first announced. I wanted to get another topic going so we can have everything covered when M14 cards are merged in.
Legend Rule - Legends are now unique per "side" if you have more than one of the same Legend, you choose all but one and place them in your graveyard.
+ Clones can no longer be used as kill spells, if the AI currently uses them in this manner he should probably stop
+ Brothers Yamazaki will probably be functionally the same, so if you control multiple Brothers, you'll choose all but two to place in your graveyard.
Planeswalker Uniqueness - Same as Legend Rule.
Sideboard Simplification - Sideboards no longer need to be 0 or 15. I did this last month.
Indestructible now a keyword. No more Hidden Keyword designation for Indestructible. A bunch of card scripts will probably need to be updated. Probably the biggest change is cards that give Indestructible to your permanents until EOT, will need to change from an Effect to a PumpAll.
Unblockable demote to definitely not a keyword. It will now be templated "Can't be blocked" No functional changes here, but we should update card scripts and any references to Unblockable in the code.
Playing Additional Lands - Exploration can no longer be bounced to grant additional land drops. The change is basically exactly how we handle playing additional lands. If we want to support Gaea's Touch we'll probably need keep track of what types of lands can be played and what type of lands have been played. But this isn't necessary for the M14 changes.
Legend Rule - Legends are now unique per "side" if you have more than one of the same Legend, you choose all but one and place them in your graveyard.
+ Clones can no longer be used as kill spells, if the AI currently uses them in this manner he should probably stop
+ Brothers Yamazaki will probably be functionally the same, so if you control multiple Brothers, you'll choose all but two to place in your graveyard.
Planeswalker Uniqueness - Same as Legend Rule.
Sideboard Simplification - Sideboards no longer need to be 0 or 15. I did this last month.
Indestructible now a keyword. No more Hidden Keyword designation for Indestructible. A bunch of card scripts will probably need to be updated. Probably the biggest change is cards that give Indestructible to your permanents until EOT, will need to change from an Effect to a PumpAll.
Unblockable demote to definitely not a keyword. It will now be templated "Can't be blocked" No functional changes here, but we should update card scripts and any references to Unblockable in the code.
Playing Additional Lands - Exploration can no longer be bounced to grant additional land drops. The change is basically exactly how we handle playing additional lands. If we want to support Gaea's Touch we'll probably need keep track of what types of lands can be played and what type of lands have been played. But this isn't necessary for the M14 changes.