Agree with you re timing being main thing , I watch alot of junior footy and there’s kids that struggle to kick 45-50m set shots in their 18th year but do it comfortably within 2 years in AFL system when they get a bit strongerIf you kick a football ten times there is every chance it will travel different distance, and that is using the same leg,no extra muscle improvement so it is timing and technique with Carmo theory Ned could build his legs up to the size of an Olympic speed skater or sprint cyclist and have the longest kick in AFL
edit: I was able to kick a ball further than most and I can tell you my legs are far from enormous
So I think you’re both right but timing and technique is the main thing , strength might be the last 5-10%
Kicking footy so often in afl system also helps timing too and definitely accuracy , have seen some bog average kickers improve significantly