Clearly you have never played a Death Knight. The reason hit and expertise don't matter is because Rune Strike can only miss, has no cooldown, and only costs a small portion of RP when it doesn't land.
They were the first tanks to need to hit in order to defend, to think otherwise is foolish. RS is the same as Jab, if it doesn't land you just press it again till it does.
You're blatantly contradicting yourself. Hit and expertise don't matter because it doesn't matter if you hit, but they have to hit?
Their AM is also an attack. *But it doesn't matter if the attack hits*, the attack is only a side effect of what the ability is really for, which is why DKs don't care as much about hit/exp. If you got no DS heal/shield and still lost the runes whenever DS missed or was dodged or parried, I bet DKs would be capping hit and exp.
If death strike wasn't a strike at all and they made up for the overall damage by redistributing it into something else, I doubt DKs would play that differently at all.
That's completely different than needing to perform *successful* attacks to gain resources that you then use for AM -- often when you don't get to try again in 1 GCD if the previous attack fails (Mangle, Keg Smash, Shield Bash, not to mention druids' rage from white crits). Honestly, I would have expected a monk to see the difference immediately. A missed, dodged or parried Keg Smash is bad news; a parried Death Strike is *impossible* and a missed or dodged one irrelevant. So of course the monk is going to care more about the consistency of their attacks.
PS Actually I do have a death knight, but it's still leveling through Wrath, so I don't necessarily know the impact of the L75 talents. Still, like you're saying, a Rune Strike miss doesn't seem all that consequential compared to missing with one of the other tanks' resource generators that has a CD, and on top of that it's explicitly immune to dodge and parry.
The fact you don't get the difference between crit and haste only being on dps gear and hit/exp being on everything is really what's mind boggling.
Tanks are free to use "dps" gear if they like the stats on it better. Some do. Agility tanks don't have dedicated tank gear in the first place, except for tier (and some of that has crit/haste IIRC). Like I said my DK is still in Wrath, where tank gear often has extra armor and stam, but after Cata that doesn't happen much (if at all), so there has to be *something* besides "get mastery on everything", doesn't there? That sounds like a very boring gear style.
The concept of "tank gear" seems to be on its way out (aside from tier, trinkets and the actual tanking shields), and it's only the low value of crit and haste for warriors that is allowing it to hang on at all.