On weapon damage using talents you get about 20% more damage from a two handed weapon. This comes out not quite a wash (0.8*1.2=0.96) but closer than for anything that uses mindpower or spellpower.
That's not how weapon damage works. You're completely wrong about the ogre oversized penalty (it's not even close to -20% damage) and you're somewhat off on your 2H to 1H comparison as well.
Attack damage is produced by multiplying 3 things together -- your character's attack strength, which is (physical power + stat ratios used by your weapon), the weapon's own power multiplier, and a random bonus on each swing set by the weapon's "range." 2-handed weapons have better range and better power as well as better ratios. Longswords have 1.4x range. This means that if your listed damage is 10, a longsword will do 10-14 per hit. Greatswords have 1.6x range; if the damage is listed as 10, it's really 10-16. If we take the averages, we can say that longswords have a +20% range bonus to damage and greatswords have +30%. Weapon power ranges from about 100 % for an iron longsword for about 190% for a voratun greatsword of massacre. Generally, I find that a 2-handed has about +20% power compared to a similar 1-handed. For instance, a dwarven-steel longsword will generally have about 120% damage and a dwarven-steel greatsword about 140%. If you only
look at range and weapon power, a 2-handed weapon does about 25
% more damage than a 1-hander.
It also has a better stat ratio. It's more complicated to figure out how important that is, because it gets combined with physical power. Assume for the moment that we are not talking about ogres, just a human choosing between a greatsword or a longsword and shield. Suppose you're around level 30. You've got perhaps 80 strength, and also 5/5 in weapon mastery. You're a Wyrmic, so weapon mastery gives you +50 raw physical power. Once your stats are scaled down, you have 62 physical power. A longsword has a 100% strength ratio, so your (Ratio+Phys.Pow) = 142. A Greatsword has 120% strength, so (Ratio+Phys.Pow.) = 158. When you fold that in with the range and power stuff from before, you find that a human wyrmic deals at least 40% more weapon damage with a greatsword than a longsword
. Now, let's look at an ogre. When an ogre wields a greatsword with a shield, they lose 20% of their physical power. Not weapon power, physical power. Physical power is scaled down and then added to a strength ratio before it multiplies with everything else. The human above had 130 raw physical power, which scaled down to 62. If they lost 20% of their physical power, then they'd have 104 raw power, 55 scaled. Thus, with a greatsword, their (strength ratio+power) would drop from 158 to 151. That's a loss of about 5% damage. An Ogre with a greatsword and shield can expect to deal about 5% less weapon damage than an ogre with just a greatsword and at least 30% more weapon damage than an ogre with a longsword and shield.
And as you continue to stack strength, it just gets more ridiculous. My level 50 ogre paladin has 148 strength and 96 physical power with just his maul equipped. When I equip my shield, my physical power would normally drop to 85 (I have +2 size, so it only drops to 90). (120%)(148)+96 = 274. I would lose 4% of my damage if I had no size boosters, but instead I lose only 2%. The only reason I even lose that much is that I'm wearing 2 artifacts that give +25 and +20 physical power but only +3 and +6 strength. If I could replace those with strength items, the damage penalty would go away almost completely.TL;DR: In the long run, ogres lose almost no weapon damage by adding a shield to their greatsword unless they have large amounts of +physical power from class skills. They always gain significant weapon damage by replacing a longsword with a greatsword.