Germany's population is falling and Turkey's is rising. Turkey will overtake Germany within less than 20 years.
Uh - where's the difference? 
Look at the treaties with the new eastern European member states - which are rather poorer than Turkey btw - the EU's otherwise liberal internal migration rules won't take effect there for years and years. You can bet any admission of Turkey will have similar paragraphs.
And don't forget that studies have showed that hordes of turks (kind of make you think of the Ottomans, but I guess that is the intention) will overwelm the EU. If the economic differences aren't enormous people ratter prefer to stay home. True, Turkey has some issues and som pretty backward areas, but is a highly developed country in world terms.
There will probably be some migration but not unskilled, more likely well educated Turks working where the pay is best.
