Make the lazy miners' default choice grow at the hard cap growth rate and you should be ok if you want voting.
I think the default block size is an orthogonal issue to the max block size.
HOWEVER: I think changing the default 'target' block size from the current, fixed 750K to the average of the size of the last N blocks would have some nice properties. It is policy-neutral (we should get out of the business of deciding the right block size and let the miners who care drive block size up or down) and if there are a significant proportion of lazy miners going with defaults it gives the system a healthy "fee pressure."