McAllister is now a television pundit for BT Sports and has co-commentated on several of the Ibrox club's games this season.
He believes the SPFL League One teams have become increasingly defensive against the Glasgow giants as the 2013/14 campaign has progressed.
He said: "I think we have covered five Rangers games now. The first one we saw them win 6-0 at Airdrie when the likes of Lewis Macleod and Nicky Law were passing it really well.
"They have pulled away from everyone and are not being tested. You have seen a change in the ball maybe going forward quicker and longer.
"Rangers were winning by big scorelines, and even had an eight in one game, so teams started to turn up thinking it wasn't going to happen to them.
"I have noticed that in the games recently. As soon as East Fife lost possession the other week, they had one up and 10 others back. It is difficult.
"Rangers have to show more guile to try and get behind but when teams defend so deep it is not always so easy."
Former Coventry City and Leeds United boss McAllister admitted he had sympathy for his old team-mate Ally McCoist at the weekend.
McCoist was heavily criticised after his team came from behind to draw the William Hill Scottish Cup game against Albion Rovers at Ibrox.
But McAllister has suffered worse results in his time in the dugout and knows that shock results can and do happen in cup competitions.
He said: "I was as surprised as anybody. I have seen them a few times and as an ex- player that has played against lower league opposition they sometimes get a wee bit of encouragement.
"They are going to raise their game and if the so-called favourite flat-lines so it can be game on.
"I had a 1-1 against Woking, who were non-league, at Coventry. I've been knocked out of the FA cup by Histon - in 10 inches of mud - when I was manager at Leeds United.
"It's incredible what happens when players see a scalp. They can play way above their level. If Rangers play up to their level then the lower team can't bridge the gap. Every manager wonders why on occasions it happens.
"People think if you play with pace, and play at a full-time level, the part-timers won't cope with it. But it's not always as easy as that."