You have to remember that when the game rolled out, the devs didn't think that stamina was a needed power.
Their definition of a "needed" power was much simpler than most of ours. Could you do the basic content in a reasonable time.
And simply stated, they were right. In I1 you could go into a mission and do it with only using rest a few times. Stamina was not needed, but the quality of gameplay it added was enormous.
Same thing with I21. You could create just about any character and survive any content the game ever created without any of the pool powers with teaming and lots of patients.
It's just that these powers combined with the IOs you could get had the ability to transform sets into machines of destruction.