When a Fighter with the "might" of a toddler and the "dexterity" of a geriatric makes a great tank it breaks all immersion.
We need restrictions on item use - no heavy armor for weak chars, for example - and no stat should be lower than 7 without the char having to deal with major penalties.
Of course this is a single player game so i see your point, it just seems silly to me.
This will always be an issue with the AI, which does not have the ability to realize that the Fighter you described above is an awful tank since it is not a threat. This isn't a problem with the attributes; all that's needed is for enemy units to take your Fighter's weak, most likely grazing disengagement attacks to get to the real threats and players will be forced to cover for their min/maxed characters or pay.
Such a clumsy and weak char shouldn't be able to move in heavy armor, nevermind swinging a heavy weapon or blocking a strong attack, it has nothing to do with the ai.
But again: it's singleplayer, use dumpstats if you want, i won't.