I think because Free Throws is a team training type of training, you wouldnt neccassarily run FT training 4-5 times in the year, just for one player.
If your top 3 players who were going to the line a lot in games, all had crapola FT's, then you could probably justify this.
I tend to run FT training once a year, over the all-star break/End of season break. So all my players get it, regardless. Just had a guy pop to Wonderous in FT. he shot 91% last year.
Another examplew would bea guy who first started playing for me (drafted) in season 12, had atrocious FT. Shot 33% that season. His FT is now awful, and shot 47% last year. But i have seen other players with atrocious FT and they only shot 11% or something horrible like that.
So i wonder if the difference in terms of percentage between, Atrocious/pitiful/awful is lager than the difference between respectable/strong/prolific. hard to say
all i know is that, if im buying a plyer, his FT level does play a huge part in the decision on whether i buy him or not.