Im sorry but the first two points are just false, logs are very reliant on player ability, not logs or potions, heres a good players alt who has an iLvl of 35x : Cherry Cordial, look her up wherever.
As for potions they make a difference but not that much, they do not make or break a parse, as for padded runs, they are few and inbetween, yes, they exist and it sucks, but they wont make nor break your percentiles, all they break are All Star points which almost nobody cares about.
Its mostly about player ability, thats the first and foremost hurdle for anyone that has low percentiles, saying its about gear, potions or padded runs.....those are just excuses, anyone can get purple with enough work and dedication, regardless of gear or whatever.