I don't mind there being a luxury resource that is acquired in a different manner than gold and diamonds and has an element of combat challenge to it. You can't obtain it just by cowering in a torchlit hole in the ground for long enough*; you need to gear up and raid, and the more you want the harder it is to get. And I'd still say it's less of a time investment than gathering lots of diamond.
And, well, other than for underwater, lightstone is just a convenience. Bloodstone is completely trivial to acquire and can take care of all your lighting needs forever.
*: Though even that's slightly harder now. The "enemy mobs spawn on light value of 7 or less" thing apparently still works on ground level, but the deeper you go, the bolder mobs get. I have bedrock-level excavations that keep surprising me with how bright they need to be to be kept critter-free.