Mohammad Amir, does not deserve to be in top 4 for anything. He isn't even in top 5 in tests and ODI's. An average of 32 in tests and 27.4 in ODI does not scream top 4 in all formats. Starc averages 28 in tests and 20 in ODI's and someone above posted he is overrated. Starc, Hazlewood and Rabada make the list. Cummins does not have a good ODI record. Shami has good ODI record but his test stats are average. Bhuvi has a decent test record but his ODI stats are mediocre. Hasan Ali has brilliant ODI record but hasn't done anything in tests yet.
So technically in terms of performances, it has to be the below 4
Starc, Hazlewood, Rabada and Boult. The rest don't qualify yet. I expect Hasan Ali to feature in top 5 soon when he plays more tests, Amir based on just one spell does not make any top 5 of any format sorry. He may have potential but cricket is decided on performances. He can bowl beautifully and can be best left arm bowler since the beginning of the game but if he averages 32 with the ball, he isn't good enough to be anywhere near the top.
Shows how bad the bowling stocks are at the moment, we are calling bowlers with averages of 28 in tests as top bowlers. That is how bad it is in test cricket at the moment.
Since his return, Amir averages 37 in tests with a SR of 80 (Shocking). Below are averages of bowlers who are considered inferior to the legend:
Mohammed Shami - Ave 24.41 SR 49 (45 wickets)
Overrated Starc - Ave 24.31 SR 43.1 (61 wickets)
N Wagner - Ave 24.41 SR 48.9 (72 wickets) - Such an underrated bowler, has out bowled Boult and Southee.
B Kumar - Ave 17.75 SR 43 (24 wickets)
3 of the above mentioned 4 do not even feature in the fab 4 and they have performed miles better than Amir. But blind fans nominating him based on one Champions Trophy spell, which was good but again one performance does not make someone great.
Even in ODI, Amir does not make top 10 list since his come back. Averages 30 with the ball in 21 games. Overrated starc in same amount of games as the legend has 14 more wickets at an average of 21. But hey, the legend bowled two good balls in Champions trophy finals so he should be better than the entire world. Amir is not even the best bowler in Pakistan, to call him best 4 bowlers to be playing right now is a huge disservice to other young bowlers playing world cricket right now. I am not even bringing spinners in to the discussion here. We are only talking about the pacers. I haven't brought in Anderson, Broad, Philander, Morkel etc. in to the discussions as well.