This article was first published in February 2017.
Calls for Arsene Wenger to leave Arsenal have intensified. He reportedly has a two-year extension on the table but if he doesn't stay, Juventus' Massimiliano Allegri, Atletico Madrid's Diego Simeone and Bournemouth's Eddie Howe are among the potential replacements.
Succeeding Wenger could prove just as difficult as replacing Sir Alex Ferguson at Manchester United. So what should Arsenal be looking for, and who might fit the criteria of replacing Wenger after 21 years?
A lack of silverware damns Wenger's later years in charge. FA Cup victories in 2014 and 2015 are the sum total of trophies since winning that same competition in 2005. But supporters crave league titles, and Arsenal haven't won the Premier League since 2004.
Both Allegri and Simeone have titles to their name. Juventus manager Allegri won Serie A with AC Milan in 2010-11 and is on course for a third Scudetto with Juve. Simeone won La Liga with Atletico in 2013-14, beating Barcelona and Real Madrid to the punch. Both have also reached -- and lost, twice in Simeone's case -- Champions League finals. Wenger has not done that since 2006.
Simeone's contract was renegotiated to end in 2018 last September -- with the plan being that he sees Atletico in their first season at their new stadium -- but that was an amendment of a previous deal taking him to 2020. The Argentinian may be looking beyond the club he has coached since 2011. Allegri is also contracted until the summer of 2018.
Another two possible contenders, Joachim Low, Germany boss until 2018, and Jorge Sampaoli, currently at Sevilla, have won international trophies, the 2014 World Cup and 2015 Copa America with Chile respectively. Two younger contenders, Borussia Dortmund's Thomas Tuchel, 43, and Bournemouth's Howe, 39, have yet to win major trophies. Tuchel was runner up in both the Bundesliga and German Cup last season, while Howe's single trophy was the 2014-15 Championship title.
Balancing the books while embracing change
Wenger's fade from an all-conquering period of winning three titles and four FA Cups from 1998 to 2005 saw him struggle to replace important players, ranging from inspirational captains Tony Adams and Patrick Vieira to star forwards Thierry Henry and Robin van Persie, as well as midfield prodigies like Samir Nasri and Cesc Fabregas.
Having to meet repayments for the Emirates Stadium reduced the spending power to replace the likes of Vieira and Henry, who departed for Juventus and Barcelona. He was also affected by the newfound billionaire-fuelled wealth of Chelsea and Manchester City. Chelsea in 2006 could offer Ashley Cole a better deal and the promise of league titles, as could City for Nasri in 2011 and United in 2012, when they plucked away Van Persie.
Arsenal have spent significantly in recent years when paying £42.4m for Mesut Ozil in 2013 and then Alexis Sanchez for £36m in 2014, yet Wenger has not been able to lavish the sums that Manchester City and Manchester United have laid out. The summer saw £91.5m spent, significantly lower than United's £150m and City's £174m. An outlay approaching £50m on Granit Xhaka and Lucas Perez is yet to yield good value.
Both Allegri and Simeone have shown excellence in rebuilding teams. Atleti lost a galaxy of stars in Sergio Aguero, Radamel Falcao and Diego Costa but continue to find others like Antoine Griezmann. Allegri lost Arturo Vidal to Bayern Munich and Paul Pogba to Manchester United in consecutive years from his Juventus team, but remains dominant in Serie A.
Nurturing young stars
In the years when Arsenal were paying back the debt on the Emirates, Wenger readjusted his approach and started building around young players. The likes of Van Persie, Fabregas, Nasri and Gael Clichy eventually departed to clubs where more money and silverware were on offer.
He has, though, maintained faith in youth, even if the careers of players like Jack Wilshere and Aaron Ramsey have never quite flowered. Hector Bellerin, Alex Iwobi and Jeff Reine-Adelaide are the latest breed, but what might happen to them under a new manager?
Simeone has made stars of Atleti academy graduates like Koke and Saul Niguez. Allegri's current Juve squad is hardly flush with youth, and neither is that of Sampaoli at Sevilla, though that perhaps reflects the pragmatism with which those clubs are run. Howe, who has revived Wilshere at Bournemouth, has gained a strong reputation for working with youngsters.
Substance over style?
Wenger transformed a club from its previous culture of "1-0 to the Arsenal" to an institution known globally for playing passing, attacking football. As David Moyes and then Louis van Gaal found out at Manchester United, adopting a more conservative style of play is a one-way ticket to unpopularity, especially when coupled with a lack of success. Even Wenger no longer gets a pass, as each season plays out in repetitious "Groundhog Day" fashion.
That might mean that Allegri or Simeone would have to deliver success quickly. Allegri's tactics at Juventus are far more based on control than predecessor Antonio Conte, while Simeone employs a rugged, often defensive style in which set pieces are a key weapon.
Howe's refusal to curb attacking philosophies at Bournemouth remind us of Wenger, though his current team's defensive problems -- only Swansea have conceded more than Bournemouth's 47 this term -- suggest a naivety. Sampaoli's Chile thrilled, and his current team play a successful attacking brand, with Sevilla four points above Simeone's Atleti in La Liga.
With Howe's inexperience and Bournemouth's recent crash in form making him a highly risky candidate, Sampaoli in his first season in European football and Tuchel struggling to repeat last season's impact at Dortmund, Simeone and Allegri are by far the strongest candidates.
But before Arsenal can move for either, they wait on a decision from Wenger himself.