I can see where those that want to punish the player for trying to min/max the game. The key here is that the GM is punishing the player not the character for playing the game in a way that they don't agree with. This game is not adversarial, but cooperative and any tactics to punish the player do not belong. An Int 5 character is going to be next to useless in any sessions that deal with social or combat aspects. He'll be a bumbling intelligent person, but unable to interact with people in a normal way. It, also, depends upon the other stats that the character has. For him to invest so heavily into one stat that the others will obviously be lacking in.
Low Brawn and he won't be able to carry any gear.
Low Agility and he won't be able to avoid most things in combat or other situations that require Agility.
Low Cunning and he will be unable to think creatively, so any information he has is merely a recitation of his memorized knowledge.
Low Willpower and he's easily swayed by everyone to their side. A charismatic BBEG will easily sway the character to join him and betray his friends.
Low Presence and he'll have a hard time interacting with others in social situations. People may get the idea that he's a creep, weird, etc... He'd be tongue twisted around others and frequently babble on while trying to pass the information he knows to others.
All of the above is not punishing the player. It is punishing the character in the areas they lack. A player that tries to go around the obvious dump stat to act normally is when the GM says, "No this is how your character acts because they have a 1 in Presence."
