Can a great system make a mediocre recording sound good?

The better your system is, especially imaging, the more it will reveal the great, good, bad, ugly.

The more you experience excellent imaging, the more you are aware of problems.

Yes it is true also in my experience...

But it is true not only with imaging,but with all other acoustic characteristic...

For example if your system give you a good listener envelopment, in some well recorded album you will be AMONG the musician on the scene...They may be around you... It will not be the case in heavily compressed music... It will be horrible... But what is hoorible on a bad audio system, stay bad on a good audio system but can become "interesting" because it take a new acoustic  meaning ... You "see" more...

I find it to be opposite. My really good system makes bad recordings almost unlistenable, It will make average recordings some better some average.

Our perspective are not exactly the same, but it is related also to the genre of music we listen to...

Most of my bad recordings in jazz or classical are more listenable in my system even if they stay bad...

But pop or rock may be exception.... The jimi Hendrix two albums i refer above are unlistenable because of compression...the mix in studio is horrible work...I hate too much mixed in studio music... I prefer natural instruments in natural acoustic room with minimal mix ... 

There's a reason why the epithet "forgiving" is quite high up there in the audiophile vocabulary.

In a poor recording a system can't reproduce something that is not there. An "accurate" system will play the good and the bad. It is not designed to fix the bad just reproduce what is in the recording.

For me it depends on what makes a mediocre recording mediocre, by the way, I'd judge a large proportion of recordings as mediocre. I've found mediocre recordings that formerly had timbre, sound staging and/or were less resolving have become much more listenable. A highly resolving system with more natural timbre or tonality will uncover information previously unheard, and presents recordings in a more forgiving manner. Recordings with these defects become more involving.

Quashed micro dynamics is one defect that's been heightened by a more resolving system. I find far too many digitally mastered recordings to suffer this malady, I can only take these recording in small doses, consecutive plays of these recordings causes me to lose interest, have to return to known high quality recordings to return to involving listening session.

Poor recordings remain poor, no help can be found for these.