Were it not for your tiny CHA score, I would have suggested a two level dip as a metal mystery Oracle to gain the ability to cast Lead Blades and increase your weapon size yet another step.
can only have one effect that increases size... oh god this is the corner case twist the rules deliberately misinterpreted wording and take stuff out of context area of expertise. So yeah size increasing "antics" might fly since lead blades doesn't "actually"increase weapon size. Won't stack with impact though.
And shouldn't with enlarge person but mileage may vary as they say.
Am trying to help. How new is your .gm? If he is that easily manipulated you shouldn't actually need any help breaking the game. You guys will do it all on your own just with what you have so far . Good day sir.
If you want damage and survivability have you conisdered the thunder and fang feat, letting you use in your case a huge earthshaker hammer in one hand, shield bashing with a huge spike shield and keeping its ac bonus
Survivability is also gained not by overpowering the opponent but layers upon layers of effects and abilities to save you.
Do you ave cover? Concealment? DR? Miss chance? Temporary hit points?
Pick up a cloak of displacement lesser, to gain a 20% miss chance. It'll help mitigate attacks on you.
Pickup juggernaut pauldrons to get a cumulative attack increase as well as some dr.
Stoneskin gives a small dr buff, but also absorbs damage.
False life or another boosters give temporary hit points.
Fortification on your armor will help decrease likelihood of a crit or sneak attack damage.
Edit: sunder and spell sunder for barbarians are very powerful. Have fun.
Sunder and improvised weapon specialization. Then go be all the ogre you can be.
How long until you put this meat seeking missile into action?