High Stats don't matter as much as players think they do. True.I think it is worth noting that everyone in the party having high stats... is fine. Doesn't really make the game harder to DM nor does it leave the characters without flaws.
Well, except when you do the reverse. When you do real, hard and harsh, mechanical rule based flaws. Well, then every player just jumps up to say no! Ask a player to have a low Constitutions so no bonus hit points. Or ask them to have a low score in an ability they need for their build. And players will not want that.
Players just love to have flaws that they can make all fluffy. My character is this or that, when I role play. But have a flaw of a clumsy character....with a very low dexterity score....oh, well that is suddenly the "wrong" kind of flaw and the player won't want to do that.