#3 Argentina and Portugal would struggle
Lionel Messi's recent four-match suspension for swearing at a match official has cast a big shadow on Argentina's 2018 World Cup qualifying prospects. With a dismal record of 5 matches lost and 2 drawn out of 8 qualifying matches played without Messi, the team and its coach need to regroup quickly and find a solution, or else we have in our hands the unthinkable prospect of a World Cup without Argentina.
It has come late – but now there is a universal recognition of the reliance that Argentina has on Messi. Having been criticised in the past for underwhelming performances at the national level, Messi has responded to his critics with stellar displays in WC 2014, Copa America 2016 and the ongoing CONMEBOL. Argentina will have a huge void to fill when Messi retires – as was demonstrated by the outcry over the captain's retirement after Copa America 2016 and his subsequent return.
Ronaldo, on the other hand, has always been a national hero – perhaps never more so than when he scored two goals in three minutes against Sweden in the 2014 WC playoffs to lead his team to Brazil.
The passion Ronaldo has for his country is also the stuff of legends; anyone who has seen the sight of a tearful Ronaldo leaving the field injured after 23 minutes in the Euro 2016 final would agree to his pride and honour of wearing the Portugal jersey.
With no clear talisman primed as a successor to Ronaldo, Portugal's future after his retirement remains hazy – although, of course, the prospect still seems a fairly long time away.
