FNS calling can't even be considered good in the modern day when he struggles to get a single attacking round on haven, historically a good map for him. For someone known for his attack side calling this is unacceptable.
FNS calling is limited by his shitty mechanics because you will almost never see him take risky lurk timings to find picks or make space or gather info.
FNS never has a good game, so you are permanently playing a 4v5 with a human drone on the team. He forces his teammates to pick up the slack because he refuses to improve his mechanics despite years as a salaried professional. Meanwhile boaster received aim coaching and looks much better mechanically, going from perma bot fragging to dropping near 30 bombs.
FNS is a problem who's benefits don't even outweigh his negatives. He is a net liability to the team and is the first person that should go when considering changes.
Having a "world class IGL" is only secondary to being a good team. Boostio nearly won vs G2 despite making some of the most horrendous attack side calls I've ever seen in T1 valorant. If your IGLing is just passable and you can make up for it with good shooting, teamplay, and protocols you will always be the better team.
Now, idk about a solution for the roster, but FNS is clearly a problem.