> Why for example, can we turn on bi-linear filtering?
Because it's free and easy. If you want to hang our integrity on it, we'll be glad to remove it and include all of your known contact information in the whatsnew in case others disagree.
> Why is Triple Buffering allowed?
This is a PC hardware implementation detail for compatibility.
> Why is there support for screen effect png files?
Because it's free and easy. Your contact information, etc, etc.
> Why allow us to run the games in 48000Hz sound?
This is a PC hardware implementation detail for compatibility. (In particular, some Creative cards slightly distort anything not played at 48 kHz). It doesn't enhance the sound quality: we always run the sound cores at their real quality and then resample as needed to fit your PC, just like we do with graphics.
> Why allow cheat files to be used?
Because the devs largely suck at playing the games, so if you want the boss of level 7 glitching out fixed in this lifetime, they have to be able to get there.
> Why allow us to any controller we want to play any game?
To facilitate the largest possible testing audience.
> Is Ms Pac-man really being authentically preserved when we can play it with an xbox > analog stick or even a steering wheel?
Namco themselves let you play it with an analog stick in the PSN/XBLA ports, and a touchscreen on iOS/Android. So apparently they disagree with you.
> Furthermore, if it's striving for 100% authenticity why is there still no force > feedback for any of the driving games that originally supported it?
We're eagerly awaiting your patch, if it meets our technical requirements (must work on Linux and Mac OS X, not just Windows).
> See where I'm going with this? All the other things have been implemented in MAME but > the line has been drawn at hardware graphical effects support....why?
None of those other things actually alter the game in any significant way. Early 3D systems had just enough geometric precision to handle their low resolutions; if you scale the entire game up it introduces errors in the graphics and gameplay which didn't actually exist. Running the audio output at 48 kHz to avoid the infamous Creative Labs distortion problems does not alter anything; Street Fighter II's samples still sound like they're being played underwater.
You want rational clarity? Here's some: you want the games enhanced because your friends point and laugh at the games you download while they download the latest Forza or DiRT or NFS. You just need to drop the right hipster terms ("vintage" or "retro") and they'll be eating out of your hand.