Here are some thought on recent events:
1) The EU can open up export markets using its 500 million market as leverage via bilateral deals not WTO. WTO is fail (see eg Doha Round).
2) David Ricardo's theories don't apply 200 yrs later. Trade has to be balanced, reciprocated in a way. Not the case eg with Germany that wants the cake and eat it too (see its views on Barroso proposals on reciprocity in world trade).
After China joined WTO, US and EU kissed manufacturing goodbye. Plus there is only a limited world market for German quality products, not much room for more players or capacity.
3) So, which does more damage to the EU economy and jobs? a) immigration or b) imports? IMO, (b)
4) Wage cost is antique economics (IMF, etc). Modern biz competes on quality and/or branding not price. Which Eurozone, EU or third country's wages do Greek or Spanish wages have to match for eg Greece and Spain to achieve competitiveness in IMF/Troika's logic?
5) Germany, USA and China have been partying in the EU market while many of the EU members are "starving". Time to raise trade walls and lower immigration walls.