So why did the 25 member states admit Bulgaria and Romania in 2007

So why did the 25 member states admit Bulgaria and Romania in 2007, even though most knew that the judiciaries were not independent, corruption was rampant and accountability weak?
Commission officials said this week that it was better to have these countries inside than outside the EU, adding that delays would slow the peaceful democratization and that reforms would lose momentum. In other words, as the Bulgarian interior minister explained, or rather complained, in an interview, reforms were being introduced, not for the sake of building a better state, but because the EU had insisted.
In defense of its decision, the commission says the 2007 enlargement was the first in which the accession treaties contained "safeguard measures."
They include withholding EU structural and agricultural funds if they are poorly administered. Although EU diplomats in both countries bemoan the corruption in the Agriculture Ministry, the rollback of reforms and procurement procedures, Brussels has taken no action, issuing only warnings. "The safety clauses are instruments," a commission official said. "The biggest stick is not necessarily the tool but the credibility of that country vis-à-vis the other member states."
That is open to question, given the performance of the other eight former Communist countries of Eastern Europe that joined the EU in 2004. Before they did, Günter Verheugen, then the enlargement commissioner, said that "this was the best-prepared enlargement ever." If compared to Greece, maybe. But compared to Spain, Portugal, Sweden, Austria, Finland, hardly.
As soon as the East European countries joined, reforms slowed, according to the World Bank and the European Bank for Reconstruction and Development.
Corruption, particularly economic corruption caused by the rapid privatization of state-owned enterprises in which Communist managers acquired assets cheaply and in dubious circumstances, was present well before enlargement. After enlargement, with EU pressure lifted, corruption increased in Latvia and Lithuania, Poland and Hungary, according to nongovernmental organizations, including Transparency International.