I think it would be better if the minimum FT rating was somewhere around 30-40%, but that would take too much balancing and too much work for it to be worth it for BB imo, unless some defense like this came out. Also, unless FTs become very effective in the game or something that is implemented that makes FTs stronger, then I don't really see a point in training free throws while I could improve a main skill. You're right, it is my choice on whether or not I train my FTs, but I don't think it should be possible for someone in this game to shoot under 20% in the line.
Anyway, this is turning into a whole different discussion than what the suggestion is about. Im still very strongly against a hack-a-Shaq defense in BB, probably because I think it is a poor tactic in real life and boring as well. Even though, yes, professionals should be able to hit free throws, it is still a cheap strategy that does not involve any skill which is why I do not like it in BB. I train OD, ID, and SB, not the "Foul the worst FT player" skill..