You still don't understand what I'm talking about. If you just attached some transactions to your block without securing them then no one cares about them. Realying nodes may change them while relaying and next miner can just ignore them and add there any transactions he wants.
Sure. And? Transactions would be malleable and not considered confirmed
at all until N confirmations. Each additional N confirmations would offer what is currently 1 block worth of added integrity. An N block fork would then be equivalent to what a 1 block fork is currently, and N block forks would become as common as 1 block forks are currently. Other than "scaling the security factor down by N" what is the problem?
In fact, this scheme doesn't change anything, miners still add transactions to block, but instead of saying that these transaction belong to block N we say that they belong to block (N-1). With all this discussion I forgot what is supposed benefit of it. If it should limit set of possible maps than it obviously won't work because miners can add arbitrary transactions (e.g. send funds to themselves) to previous block and change their seed as many times as they want.
(Here is where you "got it" before... you just at that time were confusing the two issues.)