Very difficult to be objective.

...the 323 scores very high on comfort and stability for her size. The main disadvantage I seen in my 323 is that it is difficult to point as high as a modern boat - my latest theory is that as the jib track is outside the shrouds you can't bring the jib close enough to the main to point higher (and of course that shallow, "fat" keel does not help!). As a consequence, I am generally towards the back of the pack in the local beer-can races. But I am not an avid racer - like you, more for the learning than the winning! However I should note if you are on a broad/beam reach, she is performs very well - broadly competitive with a more modern (lighter) boat - so I don't think a 323 is especially "slow".
In light winds, she moves slowly but steadily. Over winter, when the winds are lighter in NorCal, I use my big Genoa (140%). The sail size will clearly be important. A friend just got a lovely spinnaker for his 323; I did not see it in use, but with a chute I bet you would move nicely in lighter winds. As long as there is a whisper of wind, the old girl will sail.
By the way, the shallow "fat" keel may not help in pointing, but is a great asset if you are in shallower water (Lake?). I have often skimmed over shallows where modern keelboats stuck fast!
I hope this helps....