Speaking to the East Anglian Daily Times, the former Oldham, Everton and Manchester City boss said: "Whatever division we are in next season we will need to look at changes. We will need to bring in different players, perhaps not necessarily better players, just some who think more defensively.
"When we had Chris Bart-Williams fit and at his best he gave us that balance and his back problems have been costly to us defensively.
"It has not always been our fault either and nor has luck been with us. I will take my share of the blame as well. Perhaps we have been too cavalier and we need to look for a better balance."