We are already very far from original satoshi idea... so I propose to use a floating threshold. If no one is able to find a block in 2 mins then threshold will be increased. Or better say that new block threshold should be somehow linked not only to the previous 2000 blocks and separation between them but also to separation between this block and previous. It is hardly to find any hole in there... looks fine to me at first sight. It may introduce some kind of oscillation but I do not see any big flaw that can be used in attack. If you are issuing new block in just one second then your solution shall be shorter than say 5 second. If you are issuing next block after a five minute of game than your solution can be very slow and not optimal.
How can you reliable measure time interval between adjacent blocks? I don't think there is a way.
Would it be possible to use the nonce patterns in identification of human played maps/blocks giving them priority?
Would it be possible to increase the complexity of the maps with higher nonce values?
If there is a way to force bots to emulate the way humans play, would that mean safety and survival of the coin?
I'm very tired of answering the same questions. Nonce is useless, you can just change your coinbase address and always use nonce=0.