Romeu, a former Barca player, worked with Koeman at St Mary's.
He told Què t, hi jugues: "He deserves to continue at Barça and give him another year.
"The great merit of the Copa title for Barça is Koeman and more than a tactical issue is the union that is perceived in the dressing room.
"At Barça it is being key because he is betting on the youngsters, but Koeman at Southampton was criticised because he didn't give young people opportunities and they said he only gave games to players who were prepared.
"As they have them at Barça, that's why they play: Pedro, Ilaix, Ansu ..."