Play was abandoned due to rain during the third Test in Manchester, leaving the match in a draw and England with a 2-0 lead in the series with two Tests left to play.
"Flower will want the side to improve all of the time," Hussain told Sky Sports News. "I think it is a real bonus for England that Cook and Trott - their two most dependable players haven't got massive runs.
"They've chipped in here and there - Cook has got two half-centuries and Trott got some runs at Trent Bridge in the first innings - but yet England have still got enough runs because [Ian] Bell has played consistently well throughout and the tail has contributed.
"So they've managed to retain the Ashes without their two bankers having phenomenal series so far, so there is room for growth in this England side and going to Australia, so that will give Flower some kind of pleasure that it is not just the same kind of names all the time winning them games."
The fourth Test starts in Durham on Friday.