Interesting proposal.  The concerns I'd have include:

- If a vote must be used to initiate the hard fork, it should be 95%.  Note that this concept only became necessary because of the XT code fork.  Otherwise, we could of just set a date in the future and asked miners to upgrade by then. 

- Not sure why we want miners voting every week. 

   1> Miners are unlikely to want to interact.  How would this work with ASICs?  Miners probably don't want to have to update anything on a weekly basis. 

  2> Why would miner voting be needed for anything other than the hard fork?  Couldn't we just have it always calculate the block size limit periodically based on history?  I see you have a notion of this.  Buy, why as a fall-back instead of the primary method?