Can't emulate the low latency of CRT on a LCD
I'm was an avid 8bit gamer, and one thing that has gotten worse and worse (and worse) since I were a lad is 'thumb to eye' latency, or, how long a button press on the controller takes to make a change to the image on the screen, and register in the old noggin.
Lets take the 8bit SNES, connected to a CRT - its the best case, 'thumb to eye' was as low as 2ms (0.002 seconds) and at worse 18ms (PAL) or 14ms (NTSC) for a typical 2D game (VBLANK is 2.5ms).
Connect a SNES to a LCD TV, and you now have the TV's frame buffer in your way, plus the delay to change the LCD image, and if you don't have a 'game mode' on the TV, a multi-field deinterlacer too.
This adds 16~20ms to the delay, at a bare minimum, typically double that, and a good deinterlacer will add upto 40ms, enough to need the TV to buffer and delay the audio so it does not go out of sync.
Ignore the '5ms latency' claims of the manufacturers, they only measure grey to grey, black to white, even on a modern set, is still around 30~40ms.
Now go to 3D, at 30 fps, and due to 3D being renderd to a back buffer, you can add another 30~40ms to the pipe, sometimes another 30~40ms if the game buffers its graphics commands for a frame.
Put it all together, and delays of over a 10th of a second (100ms) are not uncommon in modern video games, on modern display hardware.
So, if you ever wondered why the good old games 'felt' better, IMHO, this is why.
Plasma, and OLED offer the best hope for this, but unless the 'Game Mode' on those TV's emulates the immediate display of the image signal, that was inherent in CRT we will never get back the to twitch gaming of yesteryear.