OK, back when I was working on a balance mod for E:WOM (until I took a break because of the flurry of patches coming out), as I remember, most stats were Stat/2 -10, to determine the bonus or penalty they provided. So if you for some reason had a Str less than 10, you would have a penalty to your attack strength.
At that time, I felt that ANY unit should be able to attack, even barehanded, so I dropped the -10 from the formula (so all units had a base attack of 5). To balance this, and to deal with statistical weirdness caused by the square/squareroot used in combat, I added Con/3.33 to the base defense strength. I was also working towards lessening the ranges between ordinary and epic ranges, as some weapons were simply too over the top/cheese. This actually worked very well, and even weaker monsters could still put up a fight against moderate defenses. Sure, the stronger guys would usually still win, but they'd have more bruises to show for their effort.
In any case, the way that speed was implemented in the original E:WOM was a nice way to handle initiative. While the current initiative system works pretty well, The Speed stat would fill in nicely for initiative, and being able to add bonuses to this is a nice option. Of course, in the original E:WOM, you bought 'fractional' bonuses to speed, so I would suggest a larger baseline be applied to this stat; say 10 as the baseline. As a high initiative will allow you to perform multiple actions versus very low initiatives in the current system, this is why you don't want to overdo the bonus applied by this stat.
So to summarize, I'd add these to your list.
Attack= Str/2, plus weapon strength. Yes, this DOES mean unarmed pioneers get to fight back!
Defense=Con/3.33, plus armor strength
Accuracy= Good question. Varies, with attack type determining base stats: (Str+Str+Dex) /6 for Melee, (Str+Dex)/4 for Thrown, (Str+Dex+Dex+Int)/8 for Missile. Int/2 for missile spells.
Dodge=Dex/3.33, +/- modifiers.
Initiative= Dex+Int/2, +/- modifiers.
HP Recovery/turn=Con/3 -2 (So base 1 HP/turn), +/-modifiers. The -2 base modifier can be varied by race, so Trolls and Grave Elementals might have a bonus here instead.
Spell Resistance= Con+Int/4, +/-modifiers.
Stat points added to any of the above increase the value by 1 per point (maybe more for certain stats depending on balance)
Note that Defense and Dodge get lesser stat bonuses than Attack and Accuracy. This is to favor attack versus defense slightly. Plus, Dex and Con are fairly strong stats using these modifiers, so this helps balance those stats against the other stats a bit.
Strength seems at a disadvantage here, until you realize that the amount of damage you do each round is very important. Plus, Strength gets used for a few calculations under this method, adding to it's value.
Adding HP Recovery to Con makes that stat more useful. Also, having Con figure into spell resistance adds to the usefuleness of that stat.