Can a great system make a mediocre recording sound good?

I've found that most 'poor' recordings only sound poor because the system/room I was hearing them in was not good enough to translate the acoustics of the space the recording was made in.

Exactly.....

There is still lots to hear in even a mediocre recording and a better system will do a better job of delivering what’s there.  That means a better listening experience and a better listening experience means the mediocre recording just got better. 

Exactly!

I will add  that the mediocre recording get acoustically more "interesting" and now reveal more of the original acoustical cue choices  even if he stay mediocre...We listen to it more easily, we stay with the music in it forgetting the bad recording now...

Therefore a system could be designed that would process poor recordings to sound like good ones.  But the changes made would render the performance different from the original recording.

It is not my experience....

Bad recordings stay bad... But they become listenable and very interesting now...We listen more to the original acoustical cues and we detect more what was bad INTO the recording process...

A good system put you more in touch with the acoustic process used by the recording engineer...

@kevn - good points, but how does that account for the fact that more recordings will tend to sound good to a listener than bad or mediocre, though some will most definitely sound bad or mediocre?

And some people just can't modify their listening environments as much as some people think they should be able to....

What I have found is exemplified by my run in with Jimi Hendrix ‘Are you experienced?’. When I play it on the system I have today (for nostalgia sake) it’s almost unlistenable … harsh, bright, compressed etc …

I am not familiar with this recording...

I listen a youtube copy just now... it is VERY compressed yes but not harsh nor bright on my system....

mine reveal the compression only...I dont like the compression at all...

(69) Are You Experienced? - YouTube

This other version is worst...more compressed...Neverr harsh or bright...

Jimi Hendrix - Are You Experienced? (Iowa 1968) - Bing video

One of The two worst recording among my near 9000 recording.... oufff...

I never listen rock, pop or commercial music tough...

I feel it unlistenable even if less bad recorded...Sorry...

listening that remind me why?

But it was better to listen Hendrix on the original FIRST of his recording when i had 16 years old... I never forget ... I remember Cream also vividly...The sound impression...