Sectoral employment also points to the existence of structural discrepancies. In Poland, for example, agriculture contributes over 3% to the gross value added, whereas almost 19% of the workforce is employed in this sector. Increasing rapprochement with the EU is likely to result in a major reallocation of resources even if full structural harmonisation is not likely.
At this point I should add that the accession countries generally have large current account deficits. Although such deficits are thoroughly defensible for countries that are in the process of catching up, persistent current account deficits make the economy more vulnerable to internal and external disturbances, especially if these are relatively severe and are financed short term and in foreign currency.