For me it’s pretty obvious, why Palmer is so high regarded:
As somebody mentioned before, its probably one of the most Burgundian wines of the left bank, from the most Burgundian appellation of the left bank. It therefore also has early charms and shuts down not as hard as other wines (from Pauillac, StEstephe, Saint Julien). As most Bordeaux wines are consumed within the first 20 years of their life, people hence had much better experiences with your average Palmer than with your average Leoville Las Cases (1986 not nearly ready yet).
Suckling is not feeling Palmer. 2003 got a 91 JS. I wonder if price is also a factor for score. I do that for my own score, but not sure if these guys do as well.
I think Palmer is even more expensive than second growth because a Japanese manga series about wine called The Drops of God. There are 12 wines in the manga series. Palmer is one of them.
Whether or not Palmer is the ‘best of the rest’ - non first growths from the left bank - is an open question - my vote would go to La Mission - but perhaps like Leoville Lascases, there is a sense of a first growth wannabe (but never will be) about Palmer. This is reflected in its ambitious/aggressive (take your pick) pricing strategy, and then there is the specious narrative and pretense that they have an alternative first wine (Alter Ego), the same as at Leoville Lascases (Clos du Marquis) which actually trades at a lower price than Le Petit Lion. No other estates I can think of indulges in this kind of spurious fantasy, certainly not the first growths.
Other than Selosse (which blew up for a different reason and much later), all of the 12 wines featured as the “Twelve Disciples” in the manga have appreciated more or less in line with their peers.
I’ve never found Palmer Burgundian so much as being almost right bank in style. It is very lush and plush, a real crowd-pleasing style for a left bank Bordeaux. But I sometimes find it a little soft. With that said, I haven’t had a lot of Palmer due to the combination of the price and not being sure I liked the style, so my generalizations could be off.