How many more votes would the party in second place at the last election have needed in order to have won instead?

> If some party suddenly receives a lot more votes than they polled for - it will be noticed.

Is there a mechanism by which the election could be run again (before the winners of the election have a chance to prevent this)?

> Also Estonia already has a history of (non-digital) election rigging

Or it's an argument that a voting system should have both hand-counting and digital counting, because rigging both counts is at least twice as difficult as rigging one.

As candidates & parties become more competitive, the difference in their voting shares tends to narrow. Eventually you end up with large coalitions that split the electorate fairly evenly. A small adjustment is all it'd take to tip the scales. If landslide victories are common, I'd say your political system is doing something wrong.