I did a search around the forums here and the WoW warrior forums, and have not been able to find anyone who has run numbers on tanks, threat, and + hit. The reason I ask is I noticed a significant increase in the number of dodges and parries I was getting after I dropped about 40ish hit to 15 or so.

To put it more simply, is there a sweet spot so to speak on trying for hit, or is it not significant enough to try to stack?

+ Hit rating for Warrior Tanks

also you might peruse:
[Tanks] Threat Per Second Considerations
[Warrior] AP and threat generation
[Warrior] Threat gen tips

Well it wasn't just dodge and parry, but misses as well, which I know for a fact are at least partially determined by hit, and I thought someone told me hit has something to do with dodges and parries as well.

Well, +Hit doesn't affect your chances to be Parried/Dodged. It only changes your missrate.
Against a boss I believe it's 5.6% chance to miss white damage and 8.6% to miss specials (Based on Speculation)

WARNING: Total approximations of mathematical concepts to follow

Well, roughly speaking, assuming you have no bonus to hit whatsoever, you're losing somewhere around 5.6% of your threat generation on white damage and 8.6% of your threat generation on yellow damage. Figuring that you have infinite rage and can use every ability every time it's up with a perfect threat cycle (all HS, no white damage, etc), you're losing around 8-9% of your threat generation to misses according to the assumed miss rate. Personally, I really, really hate tanking without 5% hit, plus my racial sword bonus. If I can get away with it, I do it. After I get to 5% hit, I start stacking stamina in all my gem slots. Maybe it's a waste, but as long as I have enough HP to not be one shot, that's the way I do things.

Long story short - in general warrior threat is not scaling, the reason for this is that warriors are the backbone of the game pve design - its much easier to design other classes scaling based on a nonscaling class. Most of our skills have fixed threat and the ones that at first glimpse scale are not scaling at all (Devastate, Shield Slam, Heroic Strike, White Hits). The latter are based on stats like attack power or shield block value which sadly is not scaling simply because Strength gained from gear is not increasing as we gain superior Tiers (i.e. Tier6 has much less Str than Tier5 and about the same shield block value). At the same time raid buffs are also not scaling - Windfury or Strentgh totems remain the same, so are the minor threat buffs from GotW and the like. Pots are also static buff and for good or bad soon (in 2.10) they will be out of the equasion.

The above leaves you with only a few options to increase your threat.
1. Main hand weapon - its base dps actually increases your threat as white damage is a substantial part of a warrior tank threat (if you bother to do a small research you will see that each dungeon preTBC or in TBC has 1 tank itemised main hand that offers ~5-10 mroe dps). Upgrading your MH wep upgrades your threat generation.

2. Hit rating - since you can not affect the capabilities of bosses to parry/dodge your attacks (unless with +weapon skill rating which is rarely seen on tank gear or at least not in sufficient quantities) or the speed at which you deploy white hits/specials (due to cooldowns and swing timer, unless you are using haste proc items) your only option is to affect the miss rate. Less Miss = more rage and more specials landed = more threat. Blizzard's way of itemising tank gear so far has been to introduce +hit tank items when the raid dps reaches the tank's threat limits (at least based on their own internal testing bla bla). With gems you can turn the tide in your favour.

3. Swapping tank gear with "dps" gear that provides +hit/ap/str.

To conclude - if you have access to tank items with + hit then use them. Socketing +hit gems also helps however you yourself will have to determine where is the line between +hit/stamina/avoidance since thats more of a personal choice based on your style.

To Kinkaid and Highfather:

Thanks alot, that's alot more of what I was talking about. So ideally (not really happening with present itemization), having +weapon skill and a decent amount of +hit (seems like 5-8% is somewhat reasonable) is the way to go.

That would seem to make a weapon like Mallet of the Tides off Lurker a bit more interesting then. Now Highfather, you say in regards to weapon skill, that there doesn't seem to be enough to make a difference, at what point would it?

ok, thanks

It seems very odd to me that highfather would claim that warriors don't scale. I assume this is threatwise only? Now that druids/paladins are (supposedly) MT-capable classes, wouldn't that mean that warriors would become obsolete?

I don't think this is the case, and so I'm dubious about the claim that warriors don't scale. My understanding of devastate (et al.) threat is that it has a flat BONUS, not a flat threat value. Ie, a 300 damage devastate deals 300 + 400 bonus threat, 700 total. A 350 hit deals 350+400= 750 threat. Same for heroic strike etc.

Druid attacks used to be different but were changed to flat bonuses as well. To be fair, weapon skill is much more available to druids than it is warriors (earthwarden, several dps leggings, a dps ring), but that alone isn't going to scale long term. I don't have much personal experience with paladin tanking, but theirs should be the only one that multiplies with the +90% holy damage threat. +1 spell damage equals +1.9 threat.

The amount of scaling from increased damage on a warrior isn't particularly significant, as essentially as our tank gear gets better we gain a little white dps or some shield slam damage from shield block, but right now the claim that warriors don't scale isn't that important as no, druids don't scale like they used to. It was a big topic for argument when druid threat scaled with damage and warriors didn't, but now it's not that important.

That said, I personally think +hit is a nice stat, I love it when tank gear comes itemized with some, but I really don't think gemming our armor with +8 hit rating is really the smart choice right now. For the most part I don't have threat issues, even using The Hungering Cold still. +hit is great when you need to increase your threat, but right now I'd say tanks should still be far more worried about dieing than whether or not they miss some attacks. I hope it starts coming on gear more than it does now, but I wouldn't be dropping out elunes over 8 hit rating anytime soon.

I see lots of dpsers both in my raids and on this board saying they hold back on dps...so more threat i think is still an issue.