In fact it's a important element in why Merkel has gotten a lot of internal criticism in CDU, because she haven't been active enough in seeking close integration as a tool to deal with the crisis.
Most criticism from the ranks of the CDU (and FDP) I'm aware of is the one regarding Merkel's support for EFSF and ESM. They think there's too much integration.
SPD and Greens tend to criticize Merkel's opposition to Eurobonds though. Well, Günter Oettinger too now, which is in fact a rare example of Merkel being criticized by a CDUer for not doing enough (rather than doing "too much").
Anything that has to do with the EU seems to be rather unpopular in Germany right now. Public sentiment is that either Greece and Italy should be kicked out or that Germany should withdraw on its own. And the Euro should be scrapped anyway.
Luckily for Merkel, there isn't really a anti-European force in Germany right now. Except for the Left Party maybe, but they are occupied with their own problems (and never-ending infightings). The FDP tried to pull something of an ad hoc anti-Euro campaign in the Berlin state election, which failed miserably because nobody believes the FDP anymore no matter what they say. The FDP's short-lived anti-Euro campaign came across as totally fake and desperate, more than anything else.