What difficulty? You might not have enough physical damage and in Tactician Difficulty there are enemies with elemental immunity auras and wards that confer elemental immunity (just one element). Also, you want speed at 11, since the breakpoints are even ODD number, not even. I suppose you could get items to get you that one point, but I think they removed all the craftable speed items.
High charisma is only useful to get a lot of XP for one encounter as far as I know.
The advantages of having a "crafting/blacksmith" character on a non-party guy that will not be in your party (leave them at the edge of time) is saving yourself points.
The way most people have been beating the game is using a lot of environmental effects. Sadly this makes it harder for your melee to get in most of the time. You could keep the battlefield mostly clean, but you'd need "clean" summons (summons that don't leave environmental debris) to help tank since most of the time you will be outnumbered.
