Louis van Gaal added plenty of attacking talent to his United squad in a summer spending spree that totalled in the region of £150m.
The Red Devils have conceded 13 times in nine Premier League outings - including five at Leicester City - and Cole says that the concession of "silly goals" will undermine their ambition this season.
"I think the way Manchester United are now, they're very attack-minded," Cole, who spent six years at Old Trafford, told Perform.
"A lot of the players are attack-minded - want to score goals.
"I think at times we've conceded some silly goals, but I think if you patch up all those problems, Man United will be a force."
United sit eighth in the Premier League table, 10 points adrift of leaders Chelsea.