Item Power
I have never really liked stats on gear. Having a sword infuse it's wielder with strength or agility seems like a lazy way of extending the level cap. I like items that have unique properties and special powers beyond what anyone would be able to achieve normally. (night vision on a helm, a sword that fights along side you, bow that shoots flaming arrows ect.) The effectiveness of these items should depend on the characters skill with that particular type of item and the player's ingenuity.
That being said, I think these types of magical items should also be rare and there should be a limit as to how many ungodly items a character can equip at a time.
I don't think the problem is with +stats. I think the problem is with the linear and narrow relationship those stats share with character roles and other elements within the game. It's also the fact that items carry too broad a range of stats, leading to players not so much picking the correct choice of item to upgrade, but more picking the item with bigger stats.
I wish statistics themselves played variable roles depending on your talents. Like for example, Strength increases Damage and Stamina HP--lets say that's "base". But as you select talents, or traits, or even collect items, those stats become augmented--it can even extend into what buffs you have as well. The point being that statistics should have as much depth as clicky items--+10 strength shouldn't be just +more damage.
Just a quick example...Lets take a fictional "Warrior". And lets say your game has 3 stats. (Stamina, Agility, Strength). Stamina is +HP, Strength is +Damage, Agility is +Critical Chance/Damage....But that's just base. The reality is when a character is built with talents...It should more like this.
Strength= Reduced Cool Down on X/Y skill (Depending on talents), Increased duration of "Berserk" or other abilities, Increases Armor Penetration against X or Y type targets (The game would have A dozen or so target types), Increases Jumping distance, Reduces encumbrance effect on dodge (Yeah, small features like this would be in--more variables in order to allow more minutia in crafting your character). However, unlike now--these ability augmentations would NOT be linear. +1 strength wouldn't increase damage of "Big Strike" ability by X amount, instead it would be specific numbers needed for each tier. There would be breaks and expenditures to keep the stats unique, and force you to work your gear as a concert of stats, not just +good.
I understand the above is an incredibly difficult design to keep on top of, especially in light of expansions. But I believe that unique character feeling you get from having all the variables and NOT having things work linearly, so you have to make hard choices depending on your current load out and talents, would make experimentation and character attachment all the more important.
Of course for the above to work well. A couple things would need to happen.
1.) Items could only contain a small number of stats vs the amount in the game. If you have 5 stats in your game that affect all classes. Only 2 should be available on any one piece of gear. Selecting what stat to build should be akin to designing a deck in a card game--the choices you make to fill the slot should be real and precious and the variable outcome should keep you experimenting.
2.) Rewards should be given for remaining in your spec. This does NOT mean specs should be unable to be changed. BUT rather I think it means it should work like UO did. If you want to respec, you need to earn your talent points (Or skill points) back. So, if you take 10 points out to put them somewhere else, you need to earn a few levels of Exp through grinding. You can bank these extra "respec" levels, for future use. What the respec cost would do is add enough effort to make new builds exciting, almost a gamble. While also leaving your character still open enough to change and try new things without starting over.
Just my .02$...The only reason stats are boring is because the designers made them boring. Yes, stats need to grow bigger to remain better in future expansions. But no, they don't have to be just +gooder. For a warrior +10 strength should not just be +% better. +10 strength might be worse in some situations than even +10 agility, depending on how you've stacked your gear and loaded out your talents thus far...Of course in other situations, +100 agility might not be as good as even +1 more strength. These variables and odd combos are what keep people testing. And that's how you make stats as unique as clickies, but letting the numbers have vastly different effects depending on how the totality of the number relates to all the unique points of your character.
Edit: And also, I'm not saying all stats need to be good for all classes. No. I'm saying all stats should have some value for all classes--obviously Warriors would have more abilities that value strength/stamina, BUT due to certain breaks/soft caps and other variables, there would be cases where a piece of +strength equipment wouldn't be as good as alternating that gear with another stat.