Allardyce was a cast-iron guarantee of avoiding relegation, a statistically-obsessed manager who turned a team without a recognised goalscorer into a top-10 side last season.
Rovers' owners paying hefty price for sacking Allardyce
As masterplans go, sacking the over-achieving manager without a successor in mind and suggesting that a shoestring budget and better football will propel the team into the top five does not have just one flaw. It has several.
And one game in, Blackburn Rovers are not experiencing a brave new world as much as a reality check. Saturday's 1-1 draw against West Ham United at Ewood Park should have showed Anuradha Desai, the chairwoman of Venky's, the club's new Indian owners, that the prognosis without Sam Allardyce is altogether bleaker.
"I don't know a thing about football," she said recently. Nor, the sceptics sniggered, did Allardyce. A Rovers-supporting friend described the style of play as "rugby league". But it was effective.
Allardyce was a cast-iron guarantee of avoiding relegation, a statistically-obsessed manager who played the percentages with long-ball football and dead-ball know-how, but turned a team without a recognised goalscorer into a top-10 side last season.
In his absence, Saturday was a prime example of Allardyce's expertise. On paper, a home game against the league's lowliest side is the easiest fixture of the season. His Rovers were ruthlessly reliable when it came to winning the winnable games.
Without him, they were just as dire as West Ham. Apologies for quoting the facts, but Allardyce himself would know them: the Hammers have not won away in the top flight for 27 games and 16 months. The likelihood is that their weaknesses would have been clinically exploited had he remained in charge.
It is easy to portray Steve Kean, the ambitious coach and now caretaker-manager, as the villain of the piece, given his links with the agents SEM who seem to exert an unhealthy influence.
It is probably unfair but, if he is the Desai family's proxy, it should be a lesson that attacking intent is easier discussed than implemented. Allardyce bowed out with an overly defensive 5-4-1 formation. Straight away, two men made way: the left-back Martin Olsson and the defender Phil Jones, who had been operating as a holding midfielder.
In came the creative midfielder David Dunn and the forward Mame Biram Diouf.
Rather than rendering them cavaliers, however, it resulted in the omission of Rovers' two most promising young players (Jones was ruled out, possibly for the season, after coming on as a substitute). View it that way, and Allardyce was the more forward thinking of the pair.
While it takes time to turn the efficient into entertainers, the risk in any transitional phase is that a team goes backwards. Rovers were incoherent on Saturday, neither creating chances nor appearing any easier on the eye. The contrast with their last outing at Ewood Park, the 3-0 win over Wolverhampton Wanderers, was marked.
The broader picture is that, with the exceptions of Dunn and Morten Gamst Pedersen, they lack the players to adopt a style of play for the purists. The mooted £5 million (Dh28.5m) transfer budget in January will be woefully inadequate for that.
Besides a £2.5m pay-off and a Christmas in the warmth of Dubai, the other benefit is the unusual sense of sympathy for a manager whose tactics and egotistical assertions did not always endear him to everyone.
Allardyce could annoy, but there is a deeper recognition that, within certain parameters, he was very good at his job.
Certainly his players were behind him. Saturday contained an eloquent denunciation of the owners from Ryan Nelsen, whose commitment and realism will be invaluable in the months ahead. "It would be nice when you're down in the trenches fighting to get a bit of communication," the club captain said.
It was an apt metaphor. Rovers are not just in a relegation battle. They are digging themselves into a hole.