I think Caro plays too many players these days who play at a fairly good level for a steady (low winner, low unforced error count) approach to be that successful.
It's also an approach that's somewhat limited success-wise on grass and clay.
I think Caro's had her most success against top 20 or better level when she's tried to be more proactive. For example, Caro came the lowest to beating Kim when she nearly matched her in winners for the match.
If you go back a full year to her loss to Cibulkova, it seems as soon as she plays a top 30 level player in early rounds, she's in trouble.
These plays beat Caro since Cibulkova: Vinci, Mchale, Kanepi, Pennetta, Zvonareva, Safarova, Georges, Kerber, Ivanovic. Thats besides losses to Serena, Maria, Kim, Kvitova, Radwanska.
Thats a long list of different players, and its usually early round losses.
Kanepi, Mchale & Kerber have 2 wins against her in the past year