The problem is political interface. How do I vote if politicians can just change their position just a month after the elections? Or if I can't even pin down their position, because they're not sure themselves? What am I actually voting for?

So if you are an issue-based voter, you don't vote for the right person (in which case you'd be principally evaluating their personal qualifications), instead you vote for specific policy positions (here you principally evaluate policy qualifications).

The politician who changes their views according to new information is simply less comprehensible to outside parties. It may be better to be a more easily understood politician who sticks to position in a way that is <too> sticky.