You’re too focused on hit alone.
This piece of gear wouldn’t exist, but to save me from having to make three versions, consider this series of boots:
Level 83 quest blues with 10 attack power, 10 Stamina, 10 crit, 10 hit, 10 parry.
Level 85 quest blues with 12 attack power, 12 Stamina, 12 crit, 12 hit, 12 parry.
Level 85 tier 1 raid with 14 attack power, 14 Stamina, 14 crit, 14 hit, 14 parry.
Level 85 tier 2 raid with 16 attack power, 16 Stamina, 16 crit, 16 hit, 16 parry.
When yo go from level 83 to level 85 you stay at the same amount of power relative to creatures. Why? Because the creatures are gaining levels. Their health goes up, so you need that extra AP. Their damage goes up, so you need that extra health. Your chance to crit and hit and parry them goes down, so you need those stats as well.
So far, so good.
When you start raiding, the bosses are level 88. This makes them a little harder to hit and everything, so you need that extra budget on your gear to keep up. Still not a problem.
Now let’s look at the final piece of gear. You’re going from a tier 1 raid to a tier 2 raid. The boss hits harder so you need that health. The boss has more health, so you need that attack power. But the boss is still level 88 like he was in tier 1. This means you crit him more than the previous boss, because your crit went up. You do more damage to the harder boss than to the easier boss. You also hit him more (unless you’re hit capped, which you probably are) and you parry him more.
We solved, in an awkward way, the parry problem in Icecrown by putting a debuff on you. That basically allowed the creatures to scale with your gear. We couldn’t solve the crit or hit problems, so players just became more and more powerful and eventually capped those stats (or got close to it in the case of crit). Just as players are often very worried (and sometimes rightfully so) about not scaling with gear, the bosses were not scaling with your gear. All of those problems that can happen to players when their damage (or healing or tanking) don’t scale were happening to the bosses. You were scaling too well with crit, hit and parry.
A different way to go would be that the tier 2 raid boss is actually level 89 or 90 instead of level 88. Then you’d naturally need more crit and hit and parry to face him. That makes intuitive sense, but it does some weird things to our game because creature levels were never intended to be used that way. For example, the boss would get crushing blows and resists. Even worse, it does weird things to the next tier of content. If Deathwing at the end of Cataclysm (spoiler!) is a level 93 boss, then what is the first boss at the end of the next expansion? Level 93? Level 90? Level 96?
Instead, we are just faking the bosses gaining levels. We haven’t worked out the exact mechanic yet, but imagine they are level 88++ or level 88.3 or level 88 SKULL SKULL BAD SKULL. As you get more powerful and get better gear, they get more powerful… exactly like all those bosses you handled while leveling up. Rather than critting and hitting the more dangerous opponents more often, your relative power stays about the same. You scale.