It's quite sad how people think they 'expose' leaders if they change their fucking mind. I see conservatives constantly talk about how Hillary was actually homophobic because she thought only men/women should get married...in the 90's.
There comes a time where a leader who can adapt is much more respectable than one who is never willing to change
It isn't about changing ones mind, it is about the ability to predict what the consequences of your vote are. You elect a person, but can't say how the person will decide - why bother voting at all? Sure, politician can change their opinion over time, but I want to know more or less what they'll do the next 4 years (how long they stay in power in germany), so that I can base my vote on that. Merkel actually has optimized the way she acts, so I cannot predict anything. The SPD too by the way, hence I didn't vote either one.
Again, the problem wouldn't be as pressing, if I could decide about important things directly - direct democracy as in Switzerland.