Here are two Areas that “might”require consideration in this discussion:
1. Exactness of the produced sound (deviation in the sound compared to the sound that was produced by the artist)
2. Individual preferences
There is no need to discuss difference in preferences as it is individual. When it comes to exactness I believe the issue of sound separation becomes an issue, especially with music with many layers of tones (such as orchestral). It then becomes obvious that woofer’s quickness and their numbers play a central role. The more woofers you have (assuming that they are nicely separated using high quality cross-overs), the better different tones can be separated. That is probably why many people love their Pentas. It is also a fact that newer B&O speakers tend to have more woofers. So maybe the newer Beolabs can reproduce the sounds better.
There is another topic that could be of interest with regards to sound quality of a speaker. As a classic guitar player, I prefer using guitars with cedar tops for Spanish or “romantic” songs while I generally use Spruce top guitars for pieces by Bach or Mozart, etc. The reason for that is that Cedar is a softer material which means that the tones form the six different strings of the guitar are combined in a softer way (less separation), which somehow is preferred in the case of romantic songs while spruce, with better ability t separate tones provide more exact tones, which is preferred for many western classical songs.
The relevance of this to older or newer speakers “could be” that older woofers, because of their age, loose some of their agility, dynamics or ability to quickly jump form a frequency to another. For that reason the older speakers “may have” a softer/more blurred tone that could be perceived as warmer.
But, of course, this is just a hypothesis!