I’m afraid that EU membership is not as attractive for potential new members today as it was at the times of the bi-polar world, especially for smaller members who would not have strong voice and therefore couldn’t influence the direction in which EU goes. Such members are being bullied to be adhering to vast number of formal regulations as well informal policies but they don’t get any tangible reward, e.g. economic prosperity of their citizens.
A good illustration is the current situation with decisions of VW car manufacturer where to locate their new big factory in eastern Europe. Bulgaria as a full EU member was interested in this investment, yet the company decides for non-EU member Turkey for the reason that significant number of shares in this “German” car manufacture is held by Qatar and they pushed the company management to favour a Muslim country - despite it is a country outside the single market, ruled by an unpredictable dictator and with a volatile currency. Bulgaria on the other hand, is a full member of EU, has to adhere to EU regulations, has currency pegged to €, etc.