Hmz, I respectfully disagree.
At least in Belgium there are procedures and checks in place to prevent messing around with the casted votes. Maybe other countries are more susceptible to this kind of fraud, I don't know, so pointers to examples where e.g. votes were changed when transported between polling and counting station would be appreciated.
There are many ways to rig an election, including threatening / bribing the people who count the votes whether they are located in the polling or another station, "accidentally" voiding votes when counting, not counting votes in the presence of independent witnesses, intimidating people before / when they vote, preventing people to vote at all ... All of which could lead to a 100% open score on the GODI.
In terms of old, yes, the process might be a bit dated, but let's take it to the other extreme: what if elections were entirely online, using an electronic ID card for each voter (I think voters in Estonia have the possibility to cast votes this way). What would be the acceptable "polling station" ? The municipality level ?