De Santis also stressed that Crimea had voted to join Russia - a country keen to have it - whereas the other European regions had no such plans. But they would need international partners - in defense, for example, in case they came under attack.
"They haven't thought this through properly," he said. "Catalonia, for instance, would be unlikely to be welcomed into the EU, given opposition from Spain. And English isn't their first language - so who are they going to partner with?" he asked.
Solano, however, argued that the EU should support a greater number of independent states, as it would be a good thing for Europe, boosting its productivity and making it more competitive.
"An independent Catalonia would design a new tailored tax regime adapted to our companies and also re-invest billions of euros that go to Madrid every year and never come back," Solano, who is now an adviser at the U.K. parliament, said.
"These two measures would significantly help our companies to grow and employ more people while, as a country, we would increase our contributions to the EU project in a way that would allow the EU to re-distribute part of these contributions among those EU territories that are struggling the most."
(Read more: Scotland independence: Widnae it work?)
Perhaps the bids for independence from regions like Catalonia and Venice were a foregone conclusion, given their history – but the timing indicates they were also exacerbated by Europe's financial crisis.
Indeed, Spain and Italy were two of the countries worst affected by the euro zone crisis. Spain had to request a 100 billion euro bailout from international lenders in 2012 to support its banks, while Italy's unstable political situation has seen three prime ministers in less than three years - and both are battling high unemployment rates.
"The financial crisis has not been a European-wide crisis – it's been a national crisis, and some governments have fared better than others. Spain, Italy – they're suffering more than other countries," de Santis said.
"But it's political suicide for these guys to want independence. They're not bringing a better tomorrow for their people."
—By CNBC's Katrina Bishop.Follow her on Twitter
@KatrinaBishop and Google