I am actually fine with his retirement from international football
But I do think he will be convinced to go back for WC2018.
Whilst Messi hasn't shown his Barca best for Argentina, there are more than 1 reasons for it. Piling everything on Messi is not fair, nor is it intelligent. Football is a team game, and managers have a strong influence over the results. Messi has been unfortunate with some of the garbage managers he has had to deal with for Argentina. Remember Maradona's crazy no-midfield formations? Maradona himself wouldn't do anything with that kind of formation against a top team. Seriously, if Argentina were leaking 4 goals, he wouldn't have won any international cups.
Now it is Tata Martino. Not a bad guy, but he is not a great manager. Unfortunately, Messi has had to play too many roles for Argentina. Always dropping too low to get the ball and connect the dots. Would have been great to watch prime Riquelme with prime Messi. Instead, we see that Messi has to be the person who gets the ball, carries, and passes it creatively for the likes of Aguero and Higuain to mess up.