First, your math is off. Please double check. For instance:
You somehow got your miss chance to increase by adding HBM. ( EDIT: Sorry, I see that you just mistyped the % hit part. ) You also didn't add any damage from Reckless or Bloodclaw on hits.
Yes, it seems I just mistyped that. In my calculations, miss chance stays the same and hit chance goes down b/c of HBM. Also, it was 1:30 AM when I read Bloodclaw and Reckless, and I didn't see that they were at-will powers (which seems a little broken to me as well, but whatever) ... and for some reason I thought reckless gave you a bonus to attack rolls (which was stupid of me, nothing gives THAT big of a bonus to attack rolls, even on a daily item power). And that would be where you got those numbers that I couldn't figure out
You do not add anything to Miss: damage, if the feat or item specifies adding to damage roll, as there is never a damage roll when you miss. However, Pit Fighter's +wis modifier would add, it would seem. I've edited the above to reflect this; added +1.6 DPR to Mr. Reaping Strike. Reckless Weapon / Bloodclaw Weapon / Iron Bands / Marked Scourge / Weapon Focus / Pretty much anything else do not add to miss damage. And as you say, this does clearly put 2-handers in the dust.
Yes, I believe you're right. I knew I was probably in the wrong there, and now that I'm more lucid I remember a discussion on that very topic back at the beginning of summer. So yes, with the addition of Reckless damage and no-static-damage-on-reaping-strike-miss, the tempest will be clearly ahead.
It does not. Bloodclaw deals more damage than Reckless for a Great Weapon Fighter. +18 damage on hit is better than +12 on hit, and the drop from +6d8 critical dice to +6d6 is not nearly enough to beat that.
Once again, yes, you're right. Again, I thought the item powers were dailies or encounters at the least, not at-wills. I was tired
Anyhow, I apologize for the errors in my calculations. I'd offer to fix them, but I just don't have the time at the moment, and by the time I do I expect this thread will be far past my calcs.
Ok, so yes, RAW the tempest is quite ahead of the great weapon fighter. That makes me a sad panda. At least if they're going to have the highest damage for a fighter, they should have to give up more defense. They shouldn't be able to beat a great weapon fighter in both damage and durability, that's just wrong. Anyway, I guess that's up to house rules or errata now, isn't it?
I also agree with Obryn, however, that I don't think great weapon fighters are as behind as at-will damage indicates. Like I said, at 29 there's a fighter daily doing 8[W] damage; with my sample fighter (and not counting the damage bonus from Reckless or Bloodclaw) you do around 175 on a crit with that

The next best thing a tempest can get is a power that does 3 attacks, 2[w] per hit with bonus damage for successive hits ... not nearly as impressive, in my eyes.