To be fair, Merkel's policies are fairly centrist compared to the usual CDU/CSU rhetoric and ever since the WASG split the SPD has been more center than left, t

To be fair, Merkel's policies are fairly centrist compared to the usual CDU/CSU rhetoric and ever since the WASG split the SPD has been more center than left, too. Merkel is also relatively popular with many non-CDU/CSU voters because her policies all in all have been very moderate. She's generally perceived as very static despite having had to deal with the economic crisis, the refugee situation and now Brexit. The rise of the AfD is largely a result of conservatives (who probably would have voted CDU/CSU otherwise) being upset with Merkel's handling of the refugee situation. The far left still hates her because she's a conservative, the far right hates her because she's too liberal. She's in the sweet spot where her policies are just balanced enough nobody can propose any sane alternatives that don't sound like almost exactly what she's been doing and any criticism either sounds petty or hyperbolic. The problem for the SPD is that they alienated their leftist demographic under Schröder (leading to the rise in popularity of the Linke) and later with the coalition government aside the CDU/CSU. Aside from traditional party loyalists they're now directly competing with the CDU/CSU for conservative voters. The only thing that concerns me is that the CSU is taking a lesson from the revival of the AfD (which was pretty much doomed to fail when the Euro crisis waned but was rekindled by the refugee situation) and is now spouting even more populist xenophobic rhetoric than usual. Considering how much disproportionate influence the CSU traditionally holds in the Union, this might spell trouble for the CDU internally. As an anecdote: I would never have voted for the CDU (I've previously voted for Linke and the Pirate Party) but unless one of the other parties surprises me with a great candidate, I would probably vote to re-elect Merkel.