irmo

If I adjust the picture with brightens,levels, curves it's still photography?
If I adjust the picture locally (gradient, mask, color mask, color adjusting, color balance) it's still...

whattttt??????

Equivalent aperture - says about DOF, Noise. DOF - you can't simply change with JPEG processing or any other post processing. And isn't DOF one of the main factor which makes pictures?

point of view ...

If you have 100Mpixel senzor you are awayting that all 100Mpixels will be sharp. Why else to have 100Mpixel senzor?

So yes the more Mpixel you have than more difraction will be...

you don't need it, for classic 2d viewing thats for sure .... for "normal" eyes it's something around 3Mpixel what you need. (if you have more pixels doesn't really help you, the monitor is too...