The only way for Federer to be a worthy GOAT candidate of any degree would be to:I'm sorry but those things you mentioned are really stupid, you say if he does all that you can consider him to be in Tier 1???? Cmon you are just bashing Roger... Roger achieved so much more than Borg and you put him below him???? And he is better than Sampras b/c Sampras only got in SF of RG and Roger made 5 finals and 1 win. Laver won 2 calendar slams, but on which surfaces??? Everything you said just isn't on it's place and I don't know what are you trying to achieve with this bashing
-Win atleast 2 Calender Slams
-Wins slams over a 12 year span/13 year stretch so win atleast 1 slam in 2015
-Gain a winning head to head with his main rival Nadal in slams, so gain atleast 5 more wins vs Rafa in slams than Nadal can on him
-Beats Nadal in a French Open final atleast once
-End the year ranked #1 atleast 3 more times
-Gains a winning head to head with Murray, not even strictly the slams is good enough in this case but overall
If he achieves this it would put him in the conversation with Laver, Sampras, Rosewall, Gonzales, and Borg. Right now he is in the second tier with people like Tilden, Budge, Kramer, and Perry; just above the 3rd tier of Lendl, Connors, McEnroe, Cochet, LaCoste.
Borg dominated on both grass and clay vs incredible competition. Federer dominated on grass vs weak competition, and didnt win anything on clay until a year he didnt play any of his competition. Laver was better on hard courts than clay, and dominated the hard court tournaments that did exist so he would achieved his slams even if any of them were on hard courts. His 62 slam was not legit since it was with the best players pro, but he won the pro slam in 67 so would have won his 2 slams in 67 and 69 instead of 62 and 69 I am pretty sure. Sampras has two more Wimbledons and two more year end #1s than Federer so far even vs a tougher field.
And here it is the question about competition. Why do you consider the competiton tough? Because those players found a way to beat those champions, and in 04-06 no one except Nadal found a way to beat Fed, b/c Fed rised his game far from those years standards. And this things about competition just like about the GOAT thing can be viewed from different angles. Borg didn't dominate on HC, but Fed was, Fed dominated on grass and HC so he is tied with Borg in this, but he won 14 GSs so he is better, He is far more complete player than Sampras, he is far more better than him on clay. And in Sampras's time, you could won one slam and a couple of masters and you are #1 so this days is far more difficult to get that #1 spot, what did Nadal had to win to become #1? FO, Wimby, a bunch of Masters, Olympic medal and Fed lost in first rounds or so in many tournaments etc etc etc. And you can't compare Lavers time with this, it's just not right