Coleman has pushed himself into regular first team contention at Goodison Park, scoring his first goal for the Club in the Carling Cup tie at Brentford last week and earning a first Premier League start at Fulham on Saturday.
"Seamus did really well for Blackpool and I think going there was really good for him," Armfield told evertonfc.com.
"He was a real favourite at the club, the fans loved him and I think they would have signed him had they had the chance but obviously David Moyes wouldn't want to lose a talented lad like that.
"He is very adventurous, a very progressive player and I thought when he came on against Manchester United the other week the game changed a bit.
"He has a good engine and also a very good temperament. He had a good trip at Blackpool, he went to Wembley and was part of winning promotion and it was all good experience for him."