If actually expansionary policies were pursued, the euro would not prevent them from working, and it would in fact be an excellent tool to pursue them through - Outright or veiled currency creation funding a pan-european HSR or maglev system, for example.

And dismantling the euro would cause at least short term disruptions in the trade of the euroblock, which is most emphatically not what we need right now. Heck, the need to hedge currency movements in cross border production flows means even more games for finance to play - is this really what we think will solve things?

In order for the real economy to improve, large or many projects must be undertaken that improve the efficiency and output of the world we live in - handing money to banks clearly does very little other than make bankers rich, so what we should try is to either hand money directly to the populus as a whole, or very large projects.

Mega-storage for electricity, tying together the cities of the union with an enduring transport network, or in the less physical realm, commission an creative commons  operating system written to formal-correctness proof standards. This would occupy half the coders in the union for years. And once done, would become the bedrock of all computing. Because it would be both bug-free, and free.