Complex sentence: There were concerns that the election could return a hung parliament, mainly due to the recently revised Greek electoral law, which although it preserved the 3% threshold necessary for a party to enter parliament, it would not reward as many seats for the leading party.
Split into simpler sentences: There were concerns that the election could return a hung parliament, mainly due to the recently revised Greek electoral law. Although it preserved the 3% threshold necessary for a party to enter parliament, it decreased the number of seats automatically awarded to the leading party.