I heard Nexus 5 will have a very powerful Camera which even powerful than the current Galaxy S4.

For the other hardware specification, I think it'll be standard like having Snapdragon 800, 2 or 3GB of RAM, etc.

Theoretically, YES. But, practically, NO.
Thus, the correct answer is NO. Because the phone is a physical thing and you're using it in this real world.

Because you can unroot and revert back everything to the original with ease.
So? Your phone is 100% same as the 1st day you bought... With this condition, I don't see how they say your device have warranty voided.

If you're using Samsung, they don't even care what happen to your device(rooted, unlocked or whatever). They just check the IMEI and will RMA(warranty) for you.

This post has been edited by DarkSilver: Sep 9 2013, 02:25 AM

So far, I think only XiaoMi branded phones come with UNLOCKED and ROOTED condition by default/original. Don't look down upon this brand, it has the highest specification phone currently.